Advice on low energy house

babybuilder

Hi
This is my first ever post, so here goes. I'm currently in advanced stage of drawing up plans for a new home. I'm determined to go timber framed with some sort of low energy/renewable heating system. I would like to have an actual U-value of 0.20 or lower for the whole structure and have a number of queries for anyone who has gone down this route:

1. Are there any timber-framed manufactures out there who claim that they can achieve the a low U-value of 0.20 or lower?

2. I would like to know is it possible to have an energy audit of my house plans done so as to ascertain the energy needs of the building in terms of space heating and hot water use? ( taking 1. into consideration).

3. Is it possible to build a block build house and insulate it properly. i.e. minimising thermal/cold bridges?

4. Will masonry stoves qualify for any of the renewable energy grants announced today? (i'll add this to the thread on renewable grants )?

Just to point out The house will be oriented along an east-west axis with the south-facing elevation having maximum glazing and the north facing facade having minimum glazing. overall house size 2500 sq ft.

thanks:)

mrbig

have you checked out www.sei.ie they have the software to do your own energy assement, free download.

i think when you try the energy assesment software it will clarify alot of your questions about your design.
I think you will need to look at your water heating as a seperate isssue, one thing i found to be usefull for hot water was a presurised hot water cylinder known as a pheonix, its like a big thermos, glass lined it keeps your water hot for days.

I built a timber framed house finished this year and I can't imagine that the best insulated block built house is half as well insulated. If you look at it this way you have a timber house with insulation in the studing and a cavity that even if it is bridged won't effectivly reduce the effectives as wood is a poor conductor of heat. The only reason as far as i can see to use block build is for cheapness of build, I calculated it cost me about 10k more to go timber framed on a 3,500ft2 hse, builders recomend block built because there is more moneyin it for them, however it is you who will be living with the long term cost.

the best way of having an energy efficient house imo is to insulate the hell out of it, to me this means timber frame is the only way to go, i also put extra insulation into the foundation, argon glass windows, southerly aspect for the majority of windows.
I went for underfloor heating downsatairs and rads upstairs, in the last month i have had the heating on for only two hours a day and the house is never cold.

CJhaughey

Try this link, http://www.scanhome.ie/passive.php

babybuilder

Hi Mrbig
Thanks for the advice. You just confirmed what I am going to do. It's virtually impossible to achieve a desired U-value with a block built house. Is your house a complete kit build or did you just go for the shell from the supplier and then get the sub-contractors in to do the rest? I'm looking closely at a number of firms, Griffner-Coilte, HanseHaus, Oko-Haus, Scan Homes among several others. The advantages seem to be that you,ve greater control over quality control and that the project is completed very quickly. The disadvantages are the large cost (up to €220/sq ft) and the fact that there are few of them about.

Hi Cjhaughey
Thanks for the link to Scan homes. They seem to be a very tempting option. However, they don'y give you much room for individual design. I've given my architect clear instructions that my design must be condusive to a wooden framed build yet can still incorporate my own personal design.
I know that wooden framed costs spiral when you mess around with roofs.

mrbig

I used a company called Aframe in athboy,They basicly took My design and got their engineer to do all the engineering specs. Aframe are a sister company of Atruss so they were able to give expert advice on the roof.
I went for a traditional country style house but they do prety much any thing you wan't, I found there price competitive and the quality of the kit was very good ,it was delivered to site on the agreed day six weeks after weeks after we placed the order.
I had some minor delivery problems with second fix items but no serious isues and found them very helpful troughout.
We bought the frame as a kit including second fix materials, we specified all the materials and Aframe had no problem sourcing from suppliers of our choice where necessery, this was a great service as it meant we could get alot of materials at 13% vat rate instead of 21%.
I checked out a good few others but found this company was one of the most helpfull, this alone was very important as this build was done by direct labour. I used a profesional builder to do the ground work and foundations as this is critical and where mistakes are most costly.
I wouldn't give any thought as to compromise on the design of the house and roof at this stage i recon come up with what suits you and let them figure out how to build it. i had some large spans and voids in my design,the framing company came back with the options, composite floor joists beams etc.
I think if you are going for a complicate roof you will benifit from the accuracy you get with a timber frame. From what i could gather the cost when it comes to the complexity of the roof is more relevent when its being slated. good luck with your house.

mrbig

babybuilder wrote:

Hi Mrbig
Thanks for the advice. You just confirmed what I am going to do. It's virtually impossible to achieve a desired U-value with a block built house. Is your house a complete kit build or did you just go for the shell from the supplier and then get the sub-contractors in to do the rest? I'm looking closely at a number of firms, Griffner-Coilte, HanseHaus, Oko-Haus, Scan Homes among several others. The advantages seem to be that you,ve greater control over quality control and that the project is completed very quickly. The disadvantages are the large cost (up to €220/sq ft) and the fact that there are few of them about.

Hi Cjhaughey
Thanks for the link to Scan homes. They seem to be a very tempting option. However, they don'y give you much room for individual design. I've given my architect clear instructions that my design must be condusive to a wooden framed build yet can still incorporate my own personal design.
I know that wooden framed costs spiral when you mess around with roofs.

I used a company called Aframe in athboy,They basicly took My design and got their engineer to do all the engineering specs. Aframe are a sister company of Atruss so they were able to give expert advice on the roof.
I went for a traditional country style house but they do prety much any thing you wan't, I found there price competitive and the quality of the kit was very good ,it was delivered to site on the agreed day six weeks after weeks after we placed the order.
I had some minor delivery problems with second fix items but no serious isues and found them very helpful troughout.
We bought the frame as a kit including second fix materials, we specified all the materials and Aframe had no problem sourcing from suppliers of our choice where necessery, this was a great service as it meant we could get alot of materials at 13% vat rate instead of 21%.
I checked out a good few others but found this company was one of the most helpfull, this alone was very important as this build was done by direct labour. I used a profesional builder to do the ground work and foundations as this is critical and where mistakes are most costly.
I wouldn't give any thought as to compromise on the design of the house and roof at this stage i recon come up with what suits you and let them figure out how to build it. i had some large spans and voids in my design,the framing company came back with the options, composite floor joists beams etc.
I think if you are going for a complicate roof you will benifit from the accuracy you get with a timber frame. From what i could gather the cost when it comes to the complexity of the roof is more relevent when its being slated. good luck with your house.

babybuilder

Hi Mrbig
Thanks for the info, is greatly appreciated. Do you know if the timber they use is Irish sourced or of european origin? I've read that the latter is of better quality. I am also looking at the TEK kingspan modular construction and Griffner-Coillte. Just wondering on how quickly the shell was put together and how soon it was rain-proofed? Did you block/brick up the outside or go for one of those acrylic render finishes? Also, what type of insulation did you use? And finally, what heating source did you opt for?

Thanks

mrbig

The majority of the wood was imported as you rightly pointed out Irish timber is not suitable for the purpose.Most irish timber is used for the manufacture of OSB the company louisana pacific that manufactures it is in wexford.
The flooring joists were composite TJI joists,known as silent floor, these are excelent as they do not shrink or twist , they can cary higher loads and you can run services trough them without compromise the strength, they say up to six inch holes but I tought 4" looked like enough.
The house frame was erected in four days, the roof was felted and battened
a few days later, I ordered the windows and doors before the frame went up so the were in a week or so later (try doing that with a block build).
It has a tyvek membrane on theexterior so it is completly weather proof at this stage.
The exterior walls are block, my planning prohibited the use of brick.
I looked at several different finishes the monocouche render was a serious consideration but i saw it on a friends house and i have some reservations about the strength and porosity of it also it is very expensive.
I decided to use white sand cement and lime plaster with a nap finish.
i am very pleased with the result it is extremly durable and can be power washed if needed.
The insulation used is rockwool , the heating system is underfloor on the ground floor and rads upstairs, i am using an oil burner at the moment but i did consider a wood pellet burner, the reason I held off on it was the fuel availability is limited at the moment and i would keep the oil as a backup.
i think the wood pellets are the only really clean renable fuel at the moment,
geo thermal heat pumps use a lot of electricity, solar heat is not realy an option in our climate.I am looking into the use of bio diesel for home heating and I think that it is feasible as the DHO is around 60c p at the moment i hear bio diesl is around 70c per l.
I have a wood burning stove, I hope to use the underfloor heating troughout the winter and the stove when the weateher is milder.
My thinking on any dilemas between green v good i.e. insulation was to go with the best for the job, this is less wastefull in the long run.

babybuilder

Hi Mrbig, thanks again for the additional info. Your house sounds like was a fairly smooth project. will definitely check them out.

Viking House

1. Are there any timber-framed manufactures out there who claim that they can achieve the a low U-value of 0.20 or lower?

2. I would like to know is it possible to have an energy audit of my house plans done so as to ascertain the energy needs of the building in terms of space heating and hot water use? ( taking 1. into consideration).

3. Is it possible to build a block build house and insulate it properly. i.e. minimising thermal/cold bridges?

I can answer yes to all three questions above, and it is possible to even go as low as 0.15 with both systems.
Send me an email if you need more information.

babybuilder

Viking House wrote:

1. Are there any timber-framed manufactures out there who claim that they can achieve the a low U-value of 0.20 or lower?

2. I would like to know is it possible to have an energy audit of my house plans done so as to ascertain the energy needs of the building in terms of space heating and hot water use? ( taking 1. into consideration).

3. Is it possible to build a block build house and insulate it properly. i.e. minimising thermal/cold bridges?

I can answer yes to all three questions above, and it is possible to even go as low as 0.15 with both systems.
Send me an email if you need more information.

hi viking house

Thanks for your post. I'll give you some background info.

I'm currently drafting plans for a 2500 sq ft one and a half story house set in 2.5 acres of land in the country in Donegal. I anticipate a long siege with the planning authorites as I have sought to place as much glazing on the south facing facade with minimal glazing on the northern part. I intend having the overall U-value of the building at 0.20 or less which means i think:
1. Having a serious amount of insulation in roof and walls
2. Having windows at U-value of 1.0 or less
3. Preferrably timber framed. I think thermal mass of blocks and masonry is over rated
4. Minismising thermal bridging particularily at windows, doors, wall plate, wall floor joins.
5. air-tight as possible which would possible mean HRV

I don't trust builders in my neck of the woods and there are many of them, especially in the traditional block build. How many of the are actually qualified? I still would want to go for a contract build rather than self build( unless a project manager?)

Haven't thought of heating yet but i don't like rads and am not sure if a pellet/wood chip burner would be compatible with UFH unlike a heat pump(which is expensive). Contemplating solar. The worry is that if wood pellets become popular the demand will become greater pushing up the cost.

One of my concerns is that, having my plans nearly submitted to the planners, I would like an energy audit done to see the levels of insulation needed and where, as well as the actual heat energy requirements needed (in kW ) taking into consideration the solar gain from the glazing. Then I suppose reputable and cost effective timber manufactures have to be sought out and cost and specs of each compared. I am aware that Hanse Haus, Oko-Haus etc do high spec houses but at a price.

I would be grateful if you could give me a few pointers or additional info as to some of the issues I've raised or if you have experienced them at first hand

Thanks

Viking House

There is a lot of information about your queries on www.viking-house.net

turbine?

have a look at www.localplanet.ie for a debate on timber vs block. In many cases locally manufactured block, in a well insulated house will have a lower energy content than timber frame house of similar insulation values.

foamcutter

I supply to a number of ICF (insulated concrete forms) suppliers, they tell me that they can achieve very low U-values with their method of construction. It may be worth checking out.

Viking House

Hi Foam cutter

Can you use Eco Concrete with that system?

aislingw

It might be worth looking at Poroton blocks - see www.fbt.ie - terracotta blocks, high insulating value in themselves - single leaf system, no insulation needed for current regs and if you insulate then you can approach no-energy house levels. You can even build it yourself if you have the time and are fairly competent in that regard.

aislingw

hmm, just saw viking house's site - sorry now we didn't see this before - would have been interested in that granite wool thing! We have put a 1000 sq ft poroton extension on an old cottage - it's already plastered and everything though.

Fingalian

Hi aislingw,
Did you do the extension yourself....with the poroton blocks? Is your existing cottage mass concrete?Any photos of the extension? Thanks

aislingw

Not me personally - but himself did. Got builders to put in standard foundations etc and then hubby built the block walls - 2 storey, solid internal walls up and down - concrete first floor. He's fairly handy, ie is currently tiling and hanging doors etc, but had never built a wall before. But it all went fine and everything seems straight and true! You don't use much mortar so once the initial course is done - which fbt will do for you - it's not horrendously difficult to keep it even - says she who had nothing to do with it

Yes original is mass concrete, 1940s 2-storey cottage. Only pics I have on the pc here are at a half-way stage but will attach them here.

Fingalian

Looks good. Did you do the roof yourselves as well?

foamcutter

Sorry for the hijack,

Viking house,
I presume you can, the ICF companies that l deal with just basically supply the formwork that the concrete is poured into, the builder/self builder supplies the concrete. I'm sure they would have been asked this question already.

Viking House

My Opinion on the above mentioned ICF (insulated concrete forms) system is that neither Polysterene or Concrete are kind to the envoirnment.

Polysterene offgasses into the building.

This system is non breathable and may lead to mould at the Dew Point in the middle of the wall where the hot meets the cold.

U-value should be fine but I wouldn't expect the system to hold onto much heat when you turn off the heating as Polysterene has a low specific heat capacity/density.

The combination of Poroton and external insulation of granitewool is at the other end of the scale, has a very high density, and a decrement delay of 12 hours or more.

This means it lets the midday heat into the house at midnight and you get little variation in heat levels between day and night, about 2-3 degrees.

Concrete lets out its heat in a couple of hours and polysterene is about the same.

Concrete is a cold material with a very high embodied energy.

no-emu

Hi there,

There is a company called www.enerfina.com (lots of good info on their website + an savings calculator) that is essentially a broker in the area of residential energy housing. They will recommend FOR FREE the best deal for low energy housing solutions including insulation, wood pelet boilers, solar panels, ground pumps and so on.

There's a guy there called Gordon who's really helpful.

/no-emu