# extra insulation on self build



## jruing (30 Nov 2006)

Hi everyone first post ,but great web site .I am just after slabbing my concrete selfbuild and was considering puting insulated plasterboard on the inside of the external walls ,there is kingspan in the cavity already is there much benifit in  doing this anyone out there have it done any tips on putting on these slabs i heard about ones that are glued on to walls are these good, or are the plastic mushrooms better,considering doing main kitchen/living area 5 windows in this room 1 is 12ft high and patio door will all heat just go out windows (all double glazed low  e ptc),sitting room ,main bedroom ,thanks in advance..


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## inchbyinch (30 Nov 2006)

From what Ive read around on this site you would be better off leaving it alone. When you heat your house the concrete in the walls will absorb the heat and release it slowly acting as a form of radiator. If you put extra insulation on the inside sure you will heat up your home faster but you will lose the heat in a shot as soon as the heating is turned off as you have no mass of heat to keep the house at a constant temp. This means when your heating system turns on again it will have to heat the house from scratch. 

there are a load of threads on this website regarding insulation and look in the key posts as well.

best of luck with the build 
Inchy


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## Carpenter (30 Nov 2006)

Inchy has a point, I would suggest you consult Kingspan's technical department for advice.  By drylining the concrete you are negating the benefit of the thermal mass- net result is quick response time but quick cool down too (as Inchy suggests).  There may also be a risk of interstitial condensation, Kingspan can do an analysis for you very easily.


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## jruing (30 Nov 2006)

thanks for such prompt replies ,spoke to very helpfull guy in kingspan and confirmed that you would have a quicker heat-up time and quicker cool down time ,but was saying the block wall behind would eventually get warm !!he said for the best proformance it would be better to batten the wall before putting on the insulated sheeting to leave air gap ,its starting to sound like a big job was going to sub contract it as im all slabed out ,but maybe there arent enough benifits ,its just if kitchen living room is hard to heat it will be 2 late to say I should done this!! room about 30*17 ft wood pellet stove in centre (for heating room and hot water only )by wall ,and combination wood pellet /sawdust/grain boiler in garage heating house raditors (zoned with thermostats )


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## Johnny Boy (30 Nov 2006)

I was going to do the same but forgive my ignorance but if it is well insulated shouldn't that keep the room warmer longer.I always felt that the outside blocks were always cold in houses. As the song from Oliver goes "I have to think it out again"


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## secman (30 Nov 2006)

Just happen to be working on this part of our self build. We have the usual inner leaf board insulation, but have use a product called Low E which to all intents and purposes looks like condensed bubble wrap sandwiched between 2 layers of foil. We have placed this on inside of all exterior walls , taping the joints and have put battens over them, to which we will place the slabs. My brother used this technique on a very large high ceiling extension and he is very happy with the warm feel in the room. He claims that it warms up quickly and retains the heat long after heat is turned off.


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## Carpenter (30 Nov 2006)

Is this product called Triso Super 10 by any chance- saw it at Plan Expo, looks the job alright, but do the batten fixings which puncture the membrane not impact negatively on the performance?


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## secman (1 Dec 2006)

Battens are secured by on av 3 to 4 hilti nails and as a result the batten is extremely tight on wall, punctures would be very tightly covered by batten. Don't think its a problem, splitting hairs me thinks ! Product is actually called LOW E


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## Carpenter (1 Dec 2006)

secman said:


> Battens are secured by on av 3 to 4 hilti nails and as a result the batten is extremely tight on wall, punctures would be very tightly covered by batten. Don't think its a problem, splitting hairs me thinks ! Product is actually called LOW E


Ok, just curious about different applications and their benefits.  I think it's great that people are really starting to think about how they insulate and heat their homes, especially in this peak oil age.


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## secman (1 Dec 2006)

No probs, curiosity only dangerous to cats !


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## Optimistic (1 Dec 2006)

Hi, we have built two new builds ( one for parents and ours) and put the kingspan dry lining in both as well as the kingspan in the cavity.  If you feel the wall in a conventional house over the rads they are never warm to the hand touch. In a dry lined house they are.  Every room has an internal wall (down stairs epecially) of block build construction which will hold the heat anyway and act as the radiator that people claim, leaving you with a well insulated external wall where you loose the heat and an internal wall that will act as this radiator.  If the house heats up quickly this is more important in my opinion and the internal walls and floors will absorb the heat. My sister has not built there house with the dry lining and if they were back again they would do it.  I say do it, BUT doctors differ and patients die!!  We are very happy with our choice. Optimistic


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## Optimistic (1 Dec 2006)

I forgot to say that the insulation between cavities has to be perfect, no gaps between the sheets themselves and the wall. In pratice, does this perfection really happen!!!!  So I think it is wise to add the dry lining inside. Optimistic


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## jruing (1 Dec 2006)

hi there did this low e +battons + slab add many euros to the price ,cost per roll did u use foil back slabs then , on a different but simalar topic i installed windows (from poland)and just wondering about expanding foam is it suitable for around the edges if it bridges the cavity will it attract water /moisture ,and just above the frames in the internal doors there is about 2/half inch gap (i told block layer i was puting in saddles but told carpenter i wasnt)whats best way to finish this for plaster so as no cracks ,i was thinking of 2"*4" timber with expanding metal nailed over this any thoughts,ill have loads of other questions ,so mutch to do so little time!!


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## Carpenter (1 Dec 2006)

Sorry JR, don't mean to be smart, but your post is very difficult to read....

As for the discussion regarding use of drylining and cavity insulation- this is very interesting and it's probably an area that should be looked at by the suppliers.  I know that some blocklayers are reluctant to use the Kingspan board, they say it's too rigid, it's actually cupped and very difficult to achieve a nice tight fix to the inner leaf.  If there are any gaps between the insulation and the wall air movements are likely which dramatically affect the performance of the insulant- I remember now: Thermal Looping they call it.  For this reason the Platinum product is the blocklayers' preference, easy to cut, fix and is flexible allowing a good snug fit.  The addition of an insulated drylining will help to counterbalance any poor fitting of the cavity insulation suppose.


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## secman (1 Dec 2006)

Used 3 rolls of Low E cost €835, timber €150 and hilti cartridges €45. Labour was free -- if only !.  took 3 of us  2 full days and theres still about a days work left. Build is  a 3 gabled Dormer 2250 sq ft


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## jruing (1 Dec 2006)

Hi sorry carpenter/everyone im in work at the moment ,and theres a lot going on ,I reread post and i can bearly understand it myself ,ill take more care in future ,thanks secman for costs ,


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## micheller (1 Dec 2006)

Sorry to jump on the OP's question, would anyone care to help/comment on the following:

we are not going to dry line, instead opting for hard plaster with double the recommended insulation depth between blocks using Sheepswool insulation. 
The house will also have underfloor heating (with consequent long start up/slow down times).
Based on what has been said above about dry lining having quick heat up & down times, I'm reading that what we are doing is a good idea for heat retention and underfloor heating? Am I right on that one?

Hope that reads okay, I'm not very technically knowledgeable in this area!

Thanks in advance for any help


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## AileenF (1 Dec 2006)

Does anyone have any advice on JR UINGs question about expanding foam around the windows?


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## newbuild05 (1 Dec 2006)

hi all, we are in the process of our own self build at the moment and trying to put as much insulation in as possible.

The idea of putting extra insulation under the insulated sheets seems quite good would anyone know if there is a difference between low e and triso super 10?? and what size battons would be needed to secure and fix low e insulation to wall ??
We were going to do this with a vaulted celing we have but never thought of doing it on our external walls.


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## Teabag (1 Dec 2006)

A friend of mine pumped pollypearl beads into his new build cavity wall (along with the Kingspan insulation - is that a good idea ?


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## thefisherman (2 Dec 2006)

jr,interested in your polish windows- am getting quotes at the moment and would like to price abroad,have you a web address for them?and have they low u-values as i am going with underfloor heating


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## inchbyinch (4 Dec 2006)

micheller said:


> Sorry to jump on the OP's question, would anyone care to help/comment on the following:
> 
> we are not going to dry line, instead opting for hard plaster with double the recommended insulation depth between blocks using Sheepswool insulation.
> The house will also have underfloor heating (with consequent long start up/slow down times).
> ...


 
Hi Michelle

I must stress I'm no expert on this but when using underfloor heating the method you are proposing seems to be what is regarded as best practice....that is you heat the thermal mass and have a constant more even heat for longer periods. 

that said heating thing is a horses for courses game and optomistic made a valid point when pointing out heat up times!! they are much longer and it is best for a family home that is occupied for much of the day. 

one way to overcome this is by installing an intelligent controller that will regulate itself to have the temp at a set level at certain times during the day. It will then come on at perhaps three to be warm for five and shut off earlier as well. the more input it gets like
1)return water temp in the ufh
2)temp of the room/zone
3)temp of outside conditions
4)temp of available heat sources
the better it will be able to regulate itself. 


best of luck with the build


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## micheller (4 Dec 2006)

Cheers, that's useful to get some validation


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## jruing (4 Dec 2006)

Hi Fisherman I got the windows off a guy who brought over his own for his self build and brought over a few other lots for other people the specs for these are as follows (I am very happy with the Windows)Off-the-shelf PVC windows and doors are equipped with glazing units with low-emissivity glazing and argon gas fill, a heat-transfer coefficient U ≤ 1.1 W/m2K and acoustic resistance Rw ≤ 31 dB.


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## Froggie (5 Dec 2006)

I have used the sheepswool insulation (100mm) in my new build. This means that the insulation is in contact with both the outer and inner leafs. After the recent storms some of the internal walls are wet. I am now concerned that there is moisture cross over from the outer leaf to the inner leaf. The house is not plastered yet, but I think if I was doing it again I would use a high density board thinner than the cavity.


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## ludermor (6 Dec 2006)

Froggie,
I would think that you have a huge problem with your cavity if what you say is right. Is there any ties keeping the insulation in place? Is your insulation the exact size of the cavity? Who specced this detail


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## Froggie (7 Dec 2006)

My builder suggested this type of insulation, my Architect was not in favour. The blame must lie with me as I had the choice...


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