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.
Tuesday, April 13, 2010
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.
Wednesday, March 31, 2010
Renewables
The biggest outstanding question in my head, and probably always has been since we decided on the structure type, is the heating. I'm convinced on the comfort of Underfloor, and happy with the idea of MHRV. The problems start once we get into sourcing the energy.
Currently, you can probably supply fit & commission a condensing oil burner & tank for about €3,000. This then has a high constant outlay over the lifetime of the burner, but low capital cost.
The other option is a heat-pump. However - the area to be heated in our house is significant, and so a single pump (on the premise of single-phase electricity supply) would not cut it - certainly for a traditional build. So - I can either install 2 pumps (say 14kW + 11kW), install Oil and a single pump 16kW, or and what I had been thinking, is to chance a single 16kW with an immersion coil and bet on the insulation finish on the house to be enough to reduce the load.
I've been in an ICF house that was about 20% smaller than mine in area, but heated with a single 11kW A2W pump the inhabitants were very happy, but ran it at 18C and the property had a much smaller glazing area. Thats what pushed me to a single 16kW pump and hoping for the best.
A potential supplier modeled the heating requirement (subject to massive assumptions and average weather) and it looks like once we go below 0C we need backup from the immersion coil.
On top of all of this is solar. 'Free' energy for nearly 3 seasons sounds like a great buy, but with the Heat Pumps able to operate at night & heat a buffer during these times it's saving the night-rate electricity - currently about 8c/h.
The only thing thats not making me pull away from all and any renewables is that we will be living there long enough for the bigger ROI plays to pay out. Anything around a 20 yr horizon isn't too daunting.. more than that and I have to think hard. You can guess where I think our ROI will be!
Tuesday, March 30, 2010
A River runs through it
On site this morning to have a look at the proposals to work-around the springs right where our basement is planned to go. First - and part of the plan - we open up the side lane and put down some 4" stone for access. Second, we start clearing out some of the clay lower down and see what that does to the spring - it may move the water egress further downhill (good) or leave it as it is (not as good). With the latter we'll have to add some 6" drainage pipe covered with drainage stone and lean mix, backfilled.
The other issue to come to light is that the fall of the shale substrate goes away from the surface lower down. This will be a problem as the foundation needs to be bedded into it, and either we pull all the levels down (bad) or fill-in where the slate has fallen off. Either way is more expensive for time on the machinery and of course filler stone. Snow and Rain today makes doing anything on the site impossible, with our engineer getting stuck above his calves and still sinking right in the middle of the field. But there is always a solution, and while it will add a few grand onto the cost of this section the only other alternative is to fill it all in and stay where we are! And it could have been much worse - it could have been solid rock under the topsoil. Hopefully by the end of the week we'll have a much better idea on how it will play out.
Taking bets that when we drill the well we won't find water!
Monday, March 29, 2010
To blog?
Ok - so my initial feeling on blogging was not to, and so until now I maintained that. However - a realisation that blogging isn't for others, but for myself has made me re-evaluate that decision, and now that finally we have started the build it's the appropriate time to see if I can maintain this. Since I've never kept any type of Diary, this may be a discipline too far. But since I advised others to blog some of their adventures and ignore those who dislike the idea, I suppose I should follow my advice and hopefully have this to look back on once the pain is forgotten.
To recap on the last year we have had to:
- Obtain Planning Permission (obtained June 09)
- Apply for and be accepted in principle for a mortgage in this climate.
- Select a contractor for the structure (decided Dec 09)
- Obtain right-of-way to access the site (obtained Jan 10)
- Decide on contractors for other major items in the house (ongoing)
- Get an excavator and operator to dig (Mar 09)
As of Mar 19th we have offically started, with the excavator breaking ground. There is a massive amount of earth to be removed with the split-level over basement design requiring digging into the hillside. As of today we have excavated as per the picture.
Nothing is easy - already only 1 1/2 weeks into the build the changes and problems start.. first off the heating system may get a good bit more expensive due to the floor area of the build... that or we change tack and go with dirty old oil. Second and more immediate is while digging out the lower section for the basement we've hit 2 water springs that subsequently flooded down the road - the picture below is after we cleaned up a lot of washed out silt. The result of that is we may have to move the house back 4 feet or so and drain off the springs.
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