The notch in the middle of the photo outlines where the front door will be. Aiming for this to be filled with concrete early next week, all going well.
Thursday, April 29, 2010
Shuttering the floor
With the pads in and ready, the surface to the pads has been flattened and shaped for the raft to be poured. Yesterday, the shuttering outlining the area of the raft was constructed, today steel cages are being positioned into this as well as pipes for the basement bathroom/electrical conduit etc. The radon barrier also has to go in, but we require 1-2 fine days for laying this. Once all this is set up we can pour the first substantial concrete mass, and the first floor of our house is there. We'll be able to see the outline of the area and see the real size of the living areas, especially as the walls start to be built onto it.
The notch in the middle of the photo outlines where the front door will be. Aiming for this to be filled with concrete early next week, all going well.
The notch in the middle of the photo outlines where the front door will be. Aiming for this to be filled with concrete early next week, all going well.
Wednesday, April 21, 2010
Choosing our Architect
(Spoiler : To see what we're building a summary of the drawings can be seen here)
One of the first things we had to do, and as a result its intimidating, is finding an architect. As I know nothing about building I was concerned about being able to pick the 'right' architect, someone who could deliver a house that was different enough yet within a relatively tight budget. We hoped for something less than traditional and would stand out a bit.
The first architect we talked to was a recommendation from a friend, who incidentally has a fantastic house. We got an initial draft done of what he was thinking having looked at the site, and we were excited. But we of course wanted a couple of opinions so solicited a few more.
The second we talked to also designed a house we knew of, but on seeing the location of the site didn't think that we'd get a house of the scale we wanted through planning, and strongly implied that he didn't want to make any waves at the planning office. In my opinion, that's exactly what we're paying for (note: we're paying, not the planners!) an architect who will make the most of the regulations and policies set by the planners - push the envelope if you will. We wanted a fighter.
The final architect we wanted to talk to first sent us off to look at a couple of houses in the area he'd designed before he'd talk to us. If we were still interested then we were to ring him.. Homework. We duly went and acted suspiciously outside a number of residences, concocting unbelievable cover stories in the event we were rumbled, when in fact the truth would have probably got us an invite inside and a chocolate biscuit if lucky. On driving around remote country lanes we thought it may be difficult to see which house may be his. However, every time the house immediately sprang out at us as remarkable in its situation. They had a different look and feel and really looked like a custom house, not one pulled off a book of house plans.
So we went further, happy with our homework done we went for an interview... and it was both ways. This guy didn't want to know if we wanted a straight-forward house, he wants to design a house, not throw it up. Having blagged our way through that and accepted ;P we left with more homework - a wish list of what we wanted. Open question and deliberately so. At the end of this meeting, we knew we'd found the guy. He let his portfolio speak for itself and was only interested in delivering something out of the mundane. Looking back at no point have we regretted our choice as we're very happy with the outcome, as well as his management of the planning process.
The planning process isn't a one-way street. There can (and should be) initial meetings with planners to set the tone of what is being suggested and how that fits in with the policies for the area. The earlier that happens, the quicker the boundaries can be set and we can concentrate on designing with what will be allowed, rather than wishful thinking. The initial meeting went very well, with positive noises from the planner. Throughout the design process any significant additions or changes to the house was ran past them, usually as part of other interaction, and if we overstepped we removed and looked at it again. This is also the benefit of having a local architect on the job (either as the principal or in an advisory role) as they will be very familiar with the local restrictions and personalities involved.
With anxiety we submitted our application for planning, our house is in an 'Area of Special Interest' and with the commanding view it also suffers from the opposite - it can be seen from everywhere. While we had been in regular contact with the planners, the matter of the triangular windows at the front were a grey area up for debate. We had compromised in removing the 1 1/2 story high front window, but it was far from certain.
Thankfully after the initial period had passed we were granted permission in one pass, with conditions but nothing that was too onerous. The first hurdle was vaulted with no faults conceded! A night of (mild) celebration followed, and after that the sleeves were firmly rolled up to get to grips with what the task to hand was. From there, it took another 6 months to arrange finance, agree a contractor for the structure, and line up the major trades to follow!
One of the first things we had to do, and as a result its intimidating, is finding an architect. As I know nothing about building I was concerned about being able to pick the 'right' architect, someone who could deliver a house that was different enough yet within a relatively tight budget. We hoped for something less than traditional and would stand out a bit.
The first architect we talked to was a recommendation from a friend, who incidentally has a fantastic house. We got an initial draft done of what he was thinking having looked at the site, and we were excited. But we of course wanted a couple of opinions so solicited a few more.
The second we talked to also designed a house we knew of, but on seeing the location of the site didn't think that we'd get a house of the scale we wanted through planning, and strongly implied that he didn't want to make any waves at the planning office. In my opinion, that's exactly what we're paying for (note: we're paying, not the planners!) an architect who will make the most of the regulations and policies set by the planners - push the envelope if you will. We wanted a fighter.
The final architect we wanted to talk to first sent us off to look at a couple of houses in the area he'd designed before he'd talk to us. If we were still interested then we were to ring him.. Homework. We duly went and acted suspiciously outside a number of residences, concocting unbelievable cover stories in the event we were rumbled, when in fact the truth would have probably got us an invite inside and a chocolate biscuit if lucky. On driving around remote country lanes we thought it may be difficult to see which house may be his. However, every time the house immediately sprang out at us as remarkable in its situation. They had a different look and feel and really looked like a custom house, not one pulled off a book of house plans.
So we went further, happy with our homework done we went for an interview... and it was both ways. This guy didn't want to know if we wanted a straight-forward house, he wants to design a house, not throw it up. Having blagged our way through that and accepted ;P we left with more homework - a wish list of what we wanted. Open question and deliberately so. At the end of this meeting, we knew we'd found the guy. He let his portfolio speak for itself and was only interested in delivering something out of the mundane. Looking back at no point have we regretted our choice as we're very happy with the outcome, as well as his management of the planning process.
The planning process isn't a one-way street. There can (and should be) initial meetings with planners to set the tone of what is being suggested and how that fits in with the policies for the area. The earlier that happens, the quicker the boundaries can be set and we can concentrate on designing with what will be allowed, rather than wishful thinking. The initial meeting went very well, with positive noises from the planner. Throughout the design process any significant additions or changes to the house was ran past them, usually as part of other interaction, and if we overstepped we removed and looked at it again. This is also the benefit of having a local architect on the job (either as the principal or in an advisory role) as they will be very familiar with the local restrictions and personalities involved.
With anxiety we submitted our application for planning, our house is in an 'Area of Special Interest' and with the commanding view it also suffers from the opposite - it can be seen from everywhere. While we had been in regular contact with the planners, the matter of the triangular windows at the front were a grey area up for debate. We had compromised in removing the 1 1/2 story high front window, but it was far from certain.
Thankfully after the initial period had passed we were granted permission in one pass, with conditions but nothing that was too onerous. The first hurdle was vaulted with no faults conceded! A night of (mild) celebration followed, and after that the sleeves were firmly rolled up to get to grips with what the task to hand was. From there, it took another 6 months to arrange finance, agree a contractor for the structure, and line up the major trades to follow!
Wonderbar.. the padded foundation for extra 'lift'
Foundation pads have now been shuttered and poured. These are 'lean mix' concrete poured into wooden shutters (to define the size and shape of the concrete) that were placed into the holes dug at the end of the initial groundworks stage. These reach down to the hard rock substrate and provide a solid platform for the front of the raft to sit on, keeping it from sagging. No supermodel pictures to advertise it unfortunately!
For those that really want to know, you can learn a lot about concrete here. In short - a major determiner of concrete strength is the cement-to-water ratio - less water = stronger and a lean mix is a mix with a low water content. (The downside is that as its less fluid it's not as easy to work with).
So about 10m3 of the foundations are poured. 48hrs to cure enough, and on top of that a beam will run connecting all 4 pads and rising up to the raft. Then we have a radon barrier, and the raft itself! Then (finally) we can start building some walls and get a real feeling that the house is growing out of the ground!
22/4/2010 - The top of the pads having been poured to cap them off. Starter bars were retrospectively added to the pour above (change of mind by the engineer) and brought up
With Starter bars to hold the 2 separate pours together..
And capped off with a pour - the raft will sit on top of these.
And finally with the shutters removed and the stone leveled off (23/04/2010)
And finally with the shutters removed and the stone leveled off (23/04/2010)
Monday, April 19, 2010
Scorchio, bbrrrrrrr
The heating system has been a constant headache since day one of the project. As a technical piece it's also held the most fascination for me after the structure itself, with a background in Physics all the theory and design appeals to my illusion that I still remember what all the mumbo-jumbo was about. However despite being decided, its not entirely risk free the way we've gone.
The system we're installing is attempting to be cost neutral over the medium term, return over maybe 20 years at current prices, and if Carbon Tax and oil goes as expected then return shorter than that. It should also reduce the mess and hassle of oil, namely a dripping tank and calling for for refills.
We're fitting a flat-panel solar collector and an air-source heat pump (A2W). The solar collector is as you'd imagine - a panel set on the roof that heats a liquid (not water) that circulates through the panels into a central tank. The A2W pump looks like an air-conditioner, sucking in air one side and drawing out latent energy, blowing cooler air out the other. It works just like Geo-thermal but without the ground pipes which are unsuitable for our site (horizontal) or too expensive (vertical). This too feeds into a central tank - 600L in size.
This central tank or buffer store is kept at a temperature of about 40-55 degrees by a combination of these 2 systems, with an immersion coil as a booster in the event of these failing. From this tank, domestic hot water is acquired by drawing cold water in one end, through a large coil and emerging hot at the other end. The water in the tank isn't directly used, the energy is transferred. Similarly, the underfloor heating draws water from this tank and is pulled on demand into each heating zone. A thermostat in each zone monitors the temperature and when it falls below the requires a little motor in the UFH manifold opens and lets more hot water in.
Finally, we're adding MHRV. This is mechanical Heat-recovery Ventilation and makes a huge difference to the efficiency of the house. Air is drawn from rooms that tend to be damper (bathrooms/kitchen), up through an air pump and out. Air is drawn in by the same pump and a honeycomb in the middle of the pump allows the the two air flows to be close enough to transfer heat without the gases mixing. So you get warm fresh air pumped into rooms such as bedrooms and living rooms. The motor only uses the energy of a light bulb.
The risk we're taking? Well - the size of our build suggests a bigger heat pump than we're installing... but I'm heard a lot of anecdotal evidence to suggest the performance of an ICF house is better than an 'average' house. So I'm under-spec'ing the heat pump now and will monitor it's performance over then next year or two, and if we need to bolt on more than we can look at the options then. It's better than a bigger spend now at a cost of higher heating rates, but even with that it'll still be less than using Oil for a year.
So - now thats decided, I can stop talking about my pet topic and concentrate on the more mundane items!
The system we're installing is attempting to be cost neutral over the medium term, return over maybe 20 years at current prices, and if Carbon Tax and oil goes as expected then return shorter than that. It should also reduce the mess and hassle of oil, namely a dripping tank and calling for for refills.
We're fitting a flat-panel solar collector and an air-source heat pump (A2W). The solar collector is as you'd imagine - a panel set on the roof that heats a liquid (not water) that circulates through the panels into a central tank. The A2W pump looks like an air-conditioner, sucking in air one side and drawing out latent energy, blowing cooler air out the other. It works just like Geo-thermal but without the ground pipes which are unsuitable for our site (horizontal) or too expensive (vertical). This too feeds into a central tank - 600L in size.
This central tank or buffer store is kept at a temperature of about 40-55 degrees by a combination of these 2 systems, with an immersion coil as a booster in the event of these failing. From this tank, domestic hot water is acquired by drawing cold water in one end, through a large coil and emerging hot at the other end. The water in the tank isn't directly used, the energy is transferred. Similarly, the underfloor heating draws water from this tank and is pulled on demand into each heating zone. A thermostat in each zone monitors the temperature and when it falls below the requires a little motor in the UFH manifold opens and lets more hot water in.
Finally, we're adding MHRV. This is mechanical Heat-recovery Ventilation and makes a huge difference to the efficiency of the house. Air is drawn from rooms that tend to be damper (bathrooms/kitchen), up through an air pump and out. Air is drawn in by the same pump and a honeycomb in the middle of the pump allows the the two air flows to be close enough to transfer heat without the gases mixing. So you get warm fresh air pumped into rooms such as bedrooms and living rooms. The motor only uses the energy of a light bulb.
The risk we're taking? Well - the size of our build suggests a bigger heat pump than we're installing... but I'm heard a lot of anecdotal evidence to suggest the performance of an ICF house is better than an 'average' house. So I'm under-spec'ing the heat pump now and will monitor it's performance over then next year or two, and if we need to bolt on more than we can look at the options then. It's better than a bigger spend now at a cost of higher heating rates, but even with that it'll still be less than using Oil for a year.
So - now thats decided, I can stop talking about my pet topic and concentrate on the more mundane items!
Slowly, slowly, catchee monkey
No visible progress on site this weekend, although the engineer has signed off on the holes dug for the pads. They are in the right place, which is nice, and on Friday we had another look around as well as deciding how to route in the ESB mains, water, and other conduits required to be added into the base and walls. Its funny just how many little things there are to think about, the minutia of it can sometimes leave me slightly stressed that we're missing something that will require a lot of work to rectify.
This week I was supposed to be in the US for work, but Vulcan has deemed otherwise and so I'm left here instead. While disappointing in itself it means I can sort out a few things that would have been otherwise difficult. We've closed on the heating system, a major expense factor on par with the roof, and will be able to tie up a little legal juggling with the structure contractor easier with Lorraine and I here to sign contracts. So while nothing looks different we can start to build on the details required to ensure these items fit correctly, and avoid hacking through mass concrete at a later date. Our plumber is on standby to drop up and see what pipes he needs to lay before the floor is poured, and we'll place some ducts for electric cables to allow access to the outside front area.
Expecting the concrete pour to happen this week into the pads, Tuesday is likely. 48-hrs to cure and back fill and we can start the raft proper at that stage, and things should really start moving then.
This week I was supposed to be in the US for work, but Vulcan has deemed otherwise and so I'm left here instead. While disappointing in itself it means I can sort out a few things that would have been otherwise difficult. We've closed on the heating system, a major expense factor on par with the roof, and will be able to tie up a little legal juggling with the structure contractor easier with Lorraine and I here to sign contracts. So while nothing looks different we can start to build on the details required to ensure these items fit correctly, and avoid hacking through mass concrete at a later date. Our plumber is on standby to drop up and see what pipes he needs to lay before the floor is poured, and we'll place some ducts for electric cables to allow access to the outside front area.
Expecting the concrete pour to happen this week into the pads, Tuesday is likely. 48-hrs to cure and back fill and we can start the raft proper at that stage, and things should really start moving then.
Thursday, April 15, 2010
Preparing foundations
With the bulk excavation finished the site looks very tidy. We now have a large area at the front where the basement will sit all nicely graded off with stone. Also, we have 4 deep holes at the front for the pads for the front of the raft to sit. I believe the instruction was to dig until they found rock and as you look across the site that is found from about 2m down to nearly 3 on the side nearest the entrance. When I got there though, it was a bit of a shock to see what was actually the case. Naturally, everything you're being told is passed off as 'just a little pad of concrete" or "just have to take that back a bit" or "just a little filling of stone". When you see what the reality is then you need to adjust a bit and realize that frames of reference are not aligned. Little is dependent of whether your the one paying in my opinion, and a practical exercise in their opinion. A day of filling stone might not be a major exercise to do, but expensive to pay for. Tip number 1 - ask how much its likely to cost!
In terms of (over)spend, the excavation was 50% more than anticipated. This is mostly due to hitting the springs under the basement, the resulting drain and tidy up of the saturated and useless clay. The start of what I guess will be many overruns. We also have an as yet unknown cost of the stone filling, is was drawn on demand, so I expect another financial ripple to roll across my spreadsheet.
But - its important to be house (or site) proud and maintain it in the way you intend. With that we have the latest in ride-on mower technology keeping our lawn trim, utterly autonomous and self-maintaining.
Now steel is coming onsite that will be used in the pads and raft foundation cages, hopefully this will start today/tomorrow and we can see the first baby steps in construction. Also this brings us closer to the time we can access the first draw-down on our mortgage - up till now we've been paying all the costs out of our savings and will need to access the bank's money soon!
Wednesday, April 14, 2010
Floor plans
When we completed the excavation, we managed to mark out the various areas and room of the house for the outline, it really gave us a sense of how it will be. With the levels created, we could also stand in the various 'rooms' and see what our view would be like! We're really lucky in the site we've been given as the view is phenomenal with a panoramic view over Carlow town/county and the full range of the Wicklow Mountains in the distance. Here is a composite of the floor-plan for each level.
The view is to the east and south, allowing us to maximize it with glazing that also helps us heat the house with solar gain. But ignoring the benefit of it, we're really looking forward to being able to appreciate it daily from the various rooms. One of the more interesting ones that we hoped for in planning is in the dining room on the middle of the plans, the curved wall will be entirely glazed. Directly out that window (and 250m below) is Carlow town, and I think it will look great in there at night time with the sea of lights in that direction.
Naturally there are compromises in the plans, some people prefer separate rooms, others open living space etc. This is a nice balance for us I think. Can't wait for the walls to go up so we can really start to see it come together, hopefully completed over the next 2 months!
Tuesday, April 13, 2010
Foundation
Good news - today our engineer and builder have spec'ed out and started on the foundations. As mentioned we have the pads and beams on the front, and the other change that has come to light is that the bottom level is slightly lower than intended. In a way though, I'm happy with that, the solution is to add another layer of blocks on the basement ICF walls giving us a higher ceiling on that level, including the garage areas. These will be the main ad-hoc storage areas of the house, so more space is better.
The lane to the side has also been extended, at the end of the project this will extend all the way along the left-boundary of the property, giving us handy access all along the side - we'll add a gate towards the back and that will allow machinery into the rear of the house with ease. Great for future landscape projects, or even just cutting the grass.
So the changes to the first stage (lane, dig) have ended mostly positive towards the overall finish, better access and a higher ceiling in the basement.
The only problem now is that next week I won't be around (travelling to US for work) and its then where a number of potential issues to do with the build may arise.
The lane to the side has also been extended, at the end of the project this will extend all the way along the left-boundary of the property, giving us handy access all along the side - we'll add a gate towards the back and that will allow machinery into the rear of the house with ease. Great for future landscape projects, or even just cutting the grass.
So the changes to the first stage (lane, dig) have ended mostly positive towards the overall finish, better access and a higher ceiling in the basement.
The only problem now is that next week I won't be around (travelling to US for work) and its then where a number of potential issues to do with the build may arise.
Monday, April 12, 2010
Initial groundworks just complete
So - only 2 weeks late and still not sure how much over budget, the ground works are nearly coming to a close. With moving the house area about a little, filling in the soft ground at the front, and removing a large volume of extra clay the area now just needs to be squared off on the walls of the lower area, and graded flat. Then its time for the builder.
Thursday saw a lot of 4" stone go in, again Tom had it all arranged including vetting the quality of the stone. They were giving us stone that had been laying about for a while, and it starts to deteriorate, get brittle and start to break up. With the threat of going to a different quarry they then gave us fresh stone in the next loads and it will make a difference when it comes to the stability of the base. Our engineer was up on Saturday morning and we marked out the house on the dug area, it was exciting to be able to stand in where the rooms will be and visualize it, its getting tangible!
For most of Saturday we were getting rid of excess soil that had been dug up, but would have left no room at the front of the house, you can see in the picture above the ridge of earth to the right hand side. It gave me an appreciation of the scale as we had 2 9-ton dumpers (Tom driving the wheels off one of them) and 2 20-ton trailers hitched to tractors running non-stop for most of the day. The two trailers were a god-send as luckily another neighbour was looking for filling to make into a yard area below. He had the trailers, and we had the filling so we saved the rental cost of these and the drivers, he saved the cost of the filling. It makes for a lot more room on site.
So - next contractor in is the builder. We have an added cost over expected straight away, as rather than just a raft foundation we need to build in 3 pads of concrete connected with a ground-beam of concrete at the front of the raft - about 3/4 the distance out in the picture above, under the left wheels of the tractor above (as looking from this angle). More slippage. But naturally its better to have it stable and lasting rather than fall apart in a few years.
Final part of Saturday was cleaning the road after the vehicles were plying up and down all day. A lot of loose stone and mud were left and likely to chip a windscreen of a car. So 2 1/2 hrs of road sweeping followed, I might not be useful when it comes to construction but years of cleaning in a fast-food restaurant stood to me then.
Next week has a good forecast for weather, hopefully this allows us to get a move on with the house itself. My one and only concern now is to get weather-tight before the end of September otherwise we could be left with a few months of nothing over winter. With the building sealed we can continue the fit out inside and keep making progress.
Thursday saw a lot of 4" stone go in, again Tom had it all arranged including vetting the quality of the stone. They were giving us stone that had been laying about for a while, and it starts to deteriorate, get brittle and start to break up. With the threat of going to a different quarry they then gave us fresh stone in the next loads and it will make a difference when it comes to the stability of the base. Our engineer was up on Saturday morning and we marked out the house on the dug area, it was exciting to be able to stand in where the rooms will be and visualize it, its getting tangible!
For most of Saturday we were getting rid of excess soil that had been dug up, but would have left no room at the front of the house, you can see in the picture above the ridge of earth to the right hand side. It gave me an appreciation of the scale as we had 2 9-ton dumpers (Tom driving the wheels off one of them) and 2 20-ton trailers hitched to tractors running non-stop for most of the day. The two trailers were a god-send as luckily another neighbour was looking for filling to make into a yard area below. He had the trailers, and we had the filling so we saved the rental cost of these and the drivers, he saved the cost of the filling. It makes for a lot more room on site.
So - next contractor in is the builder. We have an added cost over expected straight away, as rather than just a raft foundation we need to build in 3 pads of concrete connected with a ground-beam of concrete at the front of the raft - about 3/4 the distance out in the picture above, under the left wheels of the tractor above (as looking from this angle). More slippage. But naturally its better to have it stable and lasting rather than fall apart in a few years.
Final part of Saturday was cleaning the road after the vehicles were plying up and down all day. A lot of loose stone and mud were left and likely to chip a windscreen of a car. So 2 1/2 hrs of road sweeping followed, I might not be useful when it comes to construction but years of cleaning in a fast-food restaurant stood to me then.
Next week has a good forecast for weather, hopefully this allows us to get a move on with the house itself. My one and only concern now is to get weather-tight before the end of September otherwise we could be left with a few months of nothing over winter. With the building sealed we can continue the fit out inside and keep making progress.
Wednesday, April 7, 2010
ICF - Insulated Concrete Forms
In Ireland, traditional build for years has been a 2 leaf cavity wall made from concrete blocks. This consists of two walls of block separated from each other by a gap of at least 1 1/2". The reason for the cavity is that masonary is pourous. and water will seep into it, through the outer leaf and into the cavity. This is particularly true in wetter climates, and anyone who has spent a summer in Ireland can attest to that. Popularity for this type of construction took off in the 1920's. If you looked around Ireland's many building sites during the boom then you'd have seen a large number of cavity walls being constructed.
Above is a handy photo of such a wall from the internet. More recently, these cavities have been packed with various insulation mechanisms, such as above, or blown-bead resin insulation. While this has dramatically increased the insulation values of these walls, there are other problems.
ICF or insulated concrete forms is a different construction mechanism. It is popular in other countries already, such as the US and Canda both whom have harsher climates (in su mmer and winter) than Ireland. ICF houses are constructed from layering these forms on top of each other (like lego), and is a quicker and stronger mechanism than block. Below is the anatomy of an ICF wall:
The ICF form is the polystyrene (like a coffee cup) on each side of the wall. These are held together with a plastic tie that is hinged to allow it to flatten for packing. The top and bottom of the form sides are crenellated and slot into each other. They weigh virtually nothing (compared to the same volume of masonary block). There is no glue or mortar to go between them, the polystyrene snuggles into the dips in the block below it. In the plastic tie there are slots to lay steel rebar both horizontally and vertically to provide extra strength to the wall and help stop cracking. Here is a rebar'ed setup
These are stacked up to a storey high, the openings for Windows and doors are cut out (its polystyrene so a knife/saw can do that) and shuttered with either timber or polystyrene to prevent the concrete escaping. Then a concrete pump is used to pour concrete in the top opening, and left to cure.
All sounds good - you now have a highly insulated (say 0.2 w/m2K) wall thats very strong. That alone might tempt you over the cavity wall, but - as they say on the shopping channel, that's not all. You also get the following
I will say that a well-constructed block house will provide every bit as good a structure as ICF - however you really need to be sure that the builder is skilled enough and pays enough attention to detail to compete. This is the real difficulty.
Also a benifit of the ICF method is that the house has a much higher mass and density. This leads to a thermal mass, i.e. a mass that will retain heat or stay cooler for longer and regulate the internal temperture more. Think of it as a shock-absorber for temperture, smoothing out the bumps of hot and cold changes. Coupled with under-floor heating these are both working in a similar way and complement each other well.
Finally about air-tightness. Every house needs to breathe. Traditional construction in Ireland has been to put holes in the walls and place a grate over them to provide this... so there are literallly big holes in the wall. Imagine that when trying to stay warm in winter with a gale howling outside! ICF houses are no different, but rather than punch big holes all over the house we'll install Mechanical Heat Recovery Ventilation. Probably another post on that, but if you are going ICF it's worth the extra investment to install MHRV.
ICF or insulated concrete forms is a different construction mechanism. It is popular in other countries already, such as the US and Canda both whom have harsher climates (in su mmer and winter) than Ireland. ICF houses are constructed from layering these forms on top of each other (like lego), and is a quicker and stronger mechanism than block. Below is the anatomy of an ICF wall:
These are stacked up to a storey high, the openings for Windows and doors are cut out (its polystyrene so a knife/saw can do that) and shuttered with either timber or polystyrene to prevent the concrete escaping. Then a concrete pump is used to pour concrete in the top opening, and left to cure.
All sounds good - you now have a highly insulated (say 0.2 w/m2K) wall thats very strong. That alone might tempt you over the cavity wall, but - as they say on the shopping channel, that's not all. You also get the following
- Airtightness - no gaps in the wall/floor junction or between bricks
- Strength - as described
- Easier construction - less room for poor quality work.
- Faster construction - foundation to roof plate for our build in perhaps 6-8 weeks
- Great sound insulation
I will say that a well-constructed block house will provide every bit as good a structure as ICF - however you really need to be sure that the builder is skilled enough and pays enough attention to detail to compete. This is the real difficulty.
Also a benifit of the ICF method is that the house has a much higher mass and density. This leads to a thermal mass, i.e. a mass that will retain heat or stay cooler for longer and regulate the internal temperture more. Think of it as a shock-absorber for temperture, smoothing out the bumps of hot and cold changes. Coupled with under-floor heating these are both working in a similar way and complement each other well.
Finally about air-tightness. Every house needs to breathe. Traditional construction in Ireland has been to put holes in the walls and place a grate over them to provide this... so there are literallly big holes in the wall. Imagine that when trying to stay warm in winter with a gale howling outside! ICF houses are no different, but rather than punch big holes all over the house we'll install Mechanical Heat Recovery Ventilation. Probably another post on that, but if you are going ICF it's worth the extra investment to install MHRV.
Estimates
Trying to estimate the cost of a build is very difficult - even when you have direct quotes for items these can and will expand as unforeseen changes or issues arise. Here is a quick breakdown of the current estimate as a percentage.
You can see there is room for this to change, and as the structure is the most planned item at the moment it is probably a little disproportional to the entire build.
You can see there is room for this to change, and as the structure is the most planned item at the moment it is probably a little disproportional to the entire build.
Tuesday, April 6, 2010
Rain stops play
After the Easter break is over, the weather has rolled in. A pity - over the Easter weekend we had decent weather that we could have finished the truck access road and started to pull back the excavation by another 2 meters - but the quarry supplying the stone was closed and we'll need to get the stone on top of the exposed hard-clay as soon as it's cleared to prevent it from mucking up from the excavator tracks. So it's an effective 3 day delay between religious holidays and the weather. Forecast for the next few days is to clear so we're on track to be ready for the foundation by week end. Funnily that's also when the operator wants to get finished, so I'd expect a push this week to do so. Suits me.
Its unknown how much all this will cost extra. On top of that, we have a huge amount of earth dug out that has to go somewhere, and it's cluttering up the site. I really want to ignore it at the moment to get a start on the house, but it won't go away on its own. The downside is that with the wet weather and mucky site we can't remove it from our field as it will track a lot of that mud on the road, and that has to be cleaned off after. Easier to wait for a dry spell (as well as the hard road onto the site) and clear it off at a later date. We're lucky in the fact that we have an area to dump it; otherwise we'd be paying for someone to take it off our hands, so the cost of it will be in the hire of the equipment to load it into a vehicle and dump it across the road.
Regarding the extra 2 meters, due to the springs discovered, and the fact the harder shale falls deeper towards the front of the house, we are pulling back the location of the house by 2 meters to reduce the amount of filling that has to go into that area. It's much cheaper to dig out than fill in so pulling it back is a better option. We'll have to step back the sides of the excavation more to prevent the house being lost into the side of the hill.
Its unknown how much all this will cost extra. On top of that, we have a huge amount of earth dug out that has to go somewhere, and it's cluttering up the site. I really want to ignore it at the moment to get a start on the house, but it won't go away on its own. The downside is that with the wet weather and mucky site we can't remove it from our field as it will track a lot of that mud on the road, and that has to be cleaned off after. Easier to wait for a dry spell (as well as the hard road onto the site) and clear it off at a later date. We're lucky in the fact that we have an area to dump it; otherwise we'd be paying for someone to take it off our hands, so the cost of it will be in the hire of the equipment to load it into a vehicle and dump it across the road.
Regarding the extra 2 meters, due to the springs discovered, and the fact the harder shale falls deeper towards the front of the house, we are pulling back the location of the house by 2 meters to reduce the amount of filling that has to go into that area. It's much cheaper to dig out than fill in so pulling it back is a better option. We'll have to step back the sides of the excavation more to prevent the house being lost into the side of the hill.
Friday, April 2, 2010
Water Drained - French Drain Installed
Today we got the drain piped and filled with 2" stone. Tom had it all arranged by the time I got there, and on site was all the drainage pipe, first load of 2" and it was underway in terms getting installed.
We are installing a French drain, named after the man who initially designed and popularised it - Mr Henry French in the mid 1800's. As above we dig a trench and bed with 2" gravel. A perforated drainage pipe sits on that and that is topped with gravel. Depending on how close to the surface, what will roll over it, and the volume of water you can use a rigid or flexible pipe in different diameters. The water can flow through the drainage stone, around the pipe and into it through the perforations. Of course it also flows out through them, but it's easier for the water to flow through the pipe.
The drain took the entire day, at the end when we started to clear the mud off the top near the gate we unearthed another spring right at the gate. While this meant more work today, it was a lot better to find it now rather than for it to bubble up when the trucks start rolling over it. The drain will extend from beyond the right hand side of the house under the basement area and down past the gate into the existing drain. Ultimately if we hadn't of caught this it would have seeped up and started to undermine the foundation. Good to have it cleared. It was impressive to see the sheer volume of water flowing through it - and it hasn't been all that wet recently!!!
Next job is that we have to start building back up to the right level with 4" stone that will allow us to build on, and get trucks up to the house area. We have a substantial amount of filling to go in which will add to the cost of this groundworks stage but can't avoid it. This is the least controllable stage, as until you get into the ground you don't know if you encounter rock, water, clay all the way etc. Once we get this built up, the house will start, and then we should be on track.
We are installing a French drain, named after the man who initially designed and popularised it - Mr Henry French in the mid 1800's. As above we dig a trench and bed with 2" gravel. A perforated drainage pipe sits on that and that is topped with gravel. Depending on how close to the surface, what will roll over it, and the volume of water you can use a rigid or flexible pipe in different diameters. The water can flow through the drainage stone, around the pipe and into it through the perforations. Of course it also flows out through them, but it's easier for the water to flow through the pipe.
The drain took the entire day, at the end when we started to clear the mud off the top near the gate we unearthed another spring right at the gate. While this meant more work today, it was a lot better to find it now rather than for it to bubble up when the trucks start rolling over it. The drain will extend from beyond the right hand side of the house under the basement area and down past the gate into the existing drain. Ultimately if we hadn't of caught this it would have seeped up and started to undermine the foundation. Good to have it cleared. It was impressive to see the sheer volume of water flowing through it - and it hasn't been all that wet recently!!!
Next job is that we have to start building back up to the right level with 4" stone that will allow us to build on, and get trucks up to the house area. We have a substantial amount of filling to go in which will add to the cost of this groundworks stage but can't avoid it. This is the least controllable stage, as until you get into the ground you don't know if you encounter rock, water, clay all the way etc. Once we get this built up, the house will start, and then we should be on track.
Thursday, April 1, 2010
Context
Big gap between the first and subsequent posts, and realising there is no context for what we're building I'll go into some detail.
The site is approx 1 Acre, heavily sloped. We have a perfect entrance already for us. The house is going to be almost exactly in the middle of the rectangular site (long edge running downhill). House will end up being about 509m2 or approx. 5500 sqft so a big house to get my teeth into! It's on family land and we're planning to live out the rest of our hopefully long lives there, if we do end up leaving for a time it won't be sold.
So the challenge is to build this in an economic time where lending is at rock bottom, the threat of job redundancies faces everyone and basically money is tight. The plans were made in slightly better times shall we say, but if we are careful and tighten down on everything we should be able to complete. The result is that we have to go the direct labour route, hiring all the contractors ourselves rather than a turnkey builder delivery. Naturally, there are gaps between what contractors do which need to be filled by yours truly, hopefully with a little help from friends, family and neighbors!
Planning went well - kudos to our architect whom I'd highly recommend for anyone. We got through with reasonable conditions and no objections. We both really love the house on paper, and are excited about starting to see it develop.
So a number of construction challenges to be overcome, a non-traditional construction methodology (ICF), and my own desire to ensure that we do it the right way - i.e. not follow the herd but understand what we're putting into the house and why. I'd like to say best practice but in reality that means different things depending on what outcome best means to you.
Time lines are estimated about a year but we have no strict deadline for a finish time. Sooner is better but only from our own desires to move into it and settle into the community. The downside of it is that its easy to let things slide a bit and maybe I'll revisit a plan to get a closer end-date, the real issue with doing that is that I'm not sure how long each part takes so it would be a heavy estimate. The first milestone is really to get weather-tight by Autumn so that internal trades can continue in bad and colder weather. The only outstanding item with that is the windows - primarily the colour but we don't yet need to order that.
The site is approx 1 Acre, heavily sloped. We have a perfect entrance already for us. The house is going to be almost exactly in the middle of the rectangular site (long edge running downhill). House will end up being about 509m2 or approx. 5500 sqft so a big house to get my teeth into! It's on family land and we're planning to live out the rest of our hopefully long lives there, if we do end up leaving for a time it won't be sold.
So the challenge is to build this in an economic time where lending is at rock bottom, the threat of job redundancies faces everyone and basically money is tight. The plans were made in slightly better times shall we say, but if we are careful and tighten down on everything we should be able to complete. The result is that we have to go the direct labour route, hiring all the contractors ourselves rather than a turnkey builder delivery. Naturally, there are gaps between what contractors do which need to be filled by yours truly, hopefully with a little help from friends, family and neighbors!
Planning went well - kudos to our architect whom I'd highly recommend for anyone. We got through with reasonable conditions and no objections. We both really love the house on paper, and are excited about starting to see it develop.
So a number of construction challenges to be overcome, a non-traditional construction methodology (ICF), and my own desire to ensure that we do it the right way - i.e. not follow the herd but understand what we're putting into the house and why. I'd like to say best practice but in reality that means different things depending on what outcome best means to you.
Time lines are estimated about a year but we have no strict deadline for a finish time. Sooner is better but only from our own desires to move into it and settle into the community. The downside of it is that its easy to let things slide a bit and maybe I'll revisit a plan to get a closer end-date, the real issue with doing that is that I'm not sure how long each part takes so it would be a heavy estimate. The first milestone is really to get weather-tight by Autumn so that internal trades can continue in bad and colder weather. The only outstanding item with that is the windows - primarily the colour but we don't yet need to order that.
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