Improving energy efficiency, but have some concerns

[digitalquill]

Hi all

I am currently embarking on an extension project at home. This involves a new area being built and opening up two rooms into one to make a kitchen diner area.

We will be getting a new kitchen and this seems the ideal opportunity to improve the energy efficiency of our home.

We are having solid wood flooring so as the floor is coming up I plan to use some form of insulation in between the joists in the floor. I will be installing hot water underfloor heating but the insulation that comes with that appears to only be thin foil and I think I can do better with a little extra cost.

Q1: What would be the best insulation to use here?

I will also insulate the exterior walls of the room (not cavity). I have planned to use either the Gyproc Thermaline or Kingspan K17 however:

Q2: Which of these in your opinions is the best?

Q3: These walls will support kitchen units, how would I fix those units to the walls given the insulation maybe as thick as 65-70mm I would require something to go right through this into the solid wall?

I had thought that I could work out the level of the fixings for those units and put a wooden batten the same thickness as the insulation and then plaster over it. This would allow fixing but would this damage the energy efficiency or cause condensation issues with the different thermal properties?

Sorry its a long post with several questions but I hope someone has been there and done it and maybe able to help!

Thanks

Matt Houldsworth

 

[mointainwalker]

I would reject any package of UFH sold with foil.

Multi-foils are very controversial anyway but their claimed values are always with 25 mm air-gap each side of foil.

They can therefore not work in UFH.

Best insulation per pound invested is fibre-wool. Staple/nail/fix some kind of netting under the joists to support it.

I'll leave the other quesions.

 

[alittlerespect]

Hi

Just a quick note: In the depths of winter underfloor heating is unlikely to provide sufficient heating, so, if you have not done so already you had better start making your contingency plans for back-up heating!

Regards

 

[digitalquill]

Hi
Thanks for the reply. Not sure what you mean about the Foil backed insulation, I have never used any UFH before, but you are saying you would just use the fibre-wool and hang the UFH on its brackets top?

By fibre-wood do you mean something like Thermafleece?

Thanks again

Matt

 

[digitalquill]

Thanks alittlerespect,

I have a large towel radiator and a second rad next to where the dining table is so we should be ok. I have had someone do he calcs on the size of the room.

Our problem may well be the opposite; we are having an orangery roof, which may have a greenhouse effect so some cooling may well be needed.

Matt

 

[mointainwalker]

Digital

You are forgetting that i have no idea what type of arrangement you are considering so don't know what brackets or anything else you are talking about.

Fibre-wool is the fluffy insulant. I use that term to avoid saying, for example , RockWool, which then fixates people on one product.

Who has done a heat-loss calc on your house and how do the the results compare with trhis UFH "package" you are using ?

P.S. I didn't realise that the Costa del 'Ull was now so sunny in winter that they needed heat-sinks rather than radiators

 

[digitalquill]

mointainwalker

Thanks that helps for the flooring, more cost effective than the solid types of insulation.

Re. heat, the extension will replace a conservatory which gets very hot in summer months. I don't think this will be a big issue as we have 4000mm of folding doors on the front of the extension opening it out into the garden, but I am concerned about the amount of glass in the new build and want to re-balance the energy loss if that makes sense.

Anyway its always sunning in Hull!

Matt

 

[digitalquill]

The calcs were done by a central heating engineer who has just fitted a new boiler, all done as part of the boiler upgrade, but in doing so we got the stage ready to install UFH putting in the pipework to take the manifold so when the extension is done all we need to do is connect the manifold and lay the UFH.

UFH is about right for the space we have in terms of output, but we are adding the towel rad mainly for tea towels etc in the kitchen area and a radiator by the dining table to give some extra cosy heat.

Matt

 

[digitalquill]

I wonder if anyone has any thoughts about the wall insulation problem?

I want to insulate the walls but do not want to compromise the ability to hang the wall units. I am looking at something like the kingspan/some form of insulation backed plasterboard.

Thanks

Matt

 

[simonjay]

I wonder if anyone has any thoughts about the wall insulation problem?

I want to insulate the walls but do not want to compromise the ability to hang the wall units. I am looking at something like the kingspan/some form of insulation backed plasterboard.

Thanks

Matt

Put up some plywood in front of the kingspan, you can hang anything off that. Screw through insulation to the wall at intervals.
Simon.

 

[ajrobb]

Put up some plywood in front of the kingspan, you can hang anything off that. Screw through insulation to the wall at intervals.

I have heard of 18mm plywood behind plasterboard but I'm not sure about having it on the surface.

I remain to be wholly convinced about PIR (Celotex or Kingspan). it seems to rely on the pentane blowing agent for improved insulation over open cell insulators (like much cheaper mineral wool). The blowing agent is gradually lost and replaced by air. Initially the conductivity of PIR is 0.021 but, after 5-10 years, this increases to 0.026 and that is probably only for whole, undamaged 2400mmx1200mm boards. Near cut edges and damaged foil, the conductivity after 5-10 years might be much higher.

For a robust wall, capable of hanging most things, I might go for 2x4 battens at 2' centres (i.e. at plywood joins and mid board) with 100mm mineral wool bats between. Cover this with 18mm plywood. Finish with Duplex (foil backed) plasterboard screwed to the ply but overlapped so the joins don't coincide.

I should also mention that there are propitiatory fixings for Kingspan that go through to the masonry. These use the plasterboard for in-plane (vertical) loads and the masonry for out of plane (horizontal) loads.

 

[digitalquill]

Thanks ajrobb that really helps, probably a cheaper solution as well even taking into account the battens,ply, insulation and plasterboard.

I guess i could skip the ply if I know where the battens are, but then again the ply would add future proofing for hanging anything in the future.

Would you go for 18mm ply? that perhaps seems to me a little overkill?

Matt

 

[ajrobb]

Would you go for 18mm ply? that perhaps seems to me a little overkill?

You can hang quite a lot just on plasterboard. I suppose even 6mm ply with the right fixings will help but you might want to trim it from 4' to 1.2m to match the plasterboard. Then put the battens at 400mm centres.

18mm ply allows you just to screw the plasterboard to the ply and anything else straight through the plasterboard to the ply without fixings. You might find the following useful:

http://www.fixingscfa.co.uk/uploads/FixingSolutionsPlasterboard.pdf

In the kitchen, I am just about to hang wall units on a Paramount Partition. I am going to fix an 18mm floorboard to the few battens there are and just hang the wall units off the floorboard with a batten behind the bottom of the units.

 

[noseall]

Thanks alittlerespect,

I have a large towel radiator and a second rad next to where the dining table is so we should be ok. I have had someone do he calcs on the size of the room.

Our problem may well be the opposite; we are having an orangery roof, which may have a greenhouse effect so some cooling may well be needed.

Matt

If you are mistakenly thinking that more glass = more heat then you are wrong. In the depths of winter you will be freezing your nuts off, particularly if you are relying upon ufh and towel rails.

This is the reason that thermal regulations prohibit the use of more than 25% glass per floor area.

 

[digitalquill]

no I am under no illusions about the cold in winter, and we are well within the regulations for % of glass. I am also sure that we have enough heating via underfloor heating and the additional rads.

I want to insulate not because I think that we cant heat the area but because I want to improve our carbon footprint and it makes sense to add this during the build