Benefits of insulation.

[Tony]

Hello, We live in an end terrace built around 1900 with a stone outer wall and brick inner. I have currently got the kitchen totally gutted, including the ceiling down and quite a bit of loose plaster missing from walls. At first I was intending patching up the missing plaster, re-boarding the ceiling and having the whole lot skimmed. I have now been wondering if there is any benefit to fitting slab insulation above the ceiling, or letting the escaping heat warm the bedroom above? Also, the house has not got cavity wall insulation, is there much benefit.when comparing energy savings to installation costs, in fitting wall insulation/plasterboard such as Kingspan K17/K18? Any advice gratefully recieved, Thanks, Tony.

[George (dicegeorge)]

i think you should kingspan the walls which go to outdoors, but not the ceiling.

and perhaps under the floor.

and draughtproof everywhere.. but with ventilation for the kitchen steam

but im not an expert, im starting out like you...

[The Natural Philosopher]

Dont bothre to insulate one room from another, but definitely insulkate any outside walls eif they are stripped back.

Kingspan and similar definitely best, and yes, the way fuel is going, payback will be pretty fast. A few years at most I'd say.

[mogga]

Apart from for sound proofing perhaps?

[Martin Bonner]

It's only worth insulating the bedroom from the kitchen if you like / really/ cold bedrooms.

Is there a cavity between the outer and the inner wall? If so, get it filled - it's a no-brainer.

If you've got the wall stripped, then I would go and fit dry-lining insulation. On the other hand, I'm a bit of a nut for extreme insulation. If you are just looking to save money, then it's probably not worth fitting insulation if you have filled the cavity (which will be cheaper).

If you haven't got a cavity, then you should definitely dry line. (Of course, the /better/ solution is to clad the /outside/ of the house, so that the walls can act as thermal mass and slow down changes in temperature.)

[Tony]

Thanks for the replies. The house has a cavity but I have been cautioned against getting cavity insulation as it alows moisture to bridge from the stone layer through to the inner brickwork. Also, in the kitchen I have a solid floor, stone flags, bedded presumably on hardcore/cinders or similar. I intend putting a water based underflor heating system under the flags and having an exposed stone floor. Part of the reason I am looking at insulation in the room is to help with the warm-up time which I think will be longer with UFH than with the radiator I currently have,(which SWMBO wants taking out to get furniture and units on all walls). Cheers, Tony.

[Mary Fisher]

Who told you that?

We've had it for years and hzve been 100% satisfied with it on all counts.

Mary>

[The Natural Philosopher]

Don't even THINK about UFH without insulation *under* the new floor.

Unless you want cosy earthworms and a cold kitchen, at huge expense./

[Martin Bonner]

I concur with Mary's response: Who told you that? If it was "a mate in the pub", ignore them; if it was a building surveyor (or architect) who has experience with buildings of similar construction, then they probably know what they are talking about (but I am surprised).

Well with UFH under stone flags, I would expect a warm-up time so long that you will (effectively) have to have it on all the time - in which case insulation won't matter (apart from the small matter of the staggering bills).

[mail]

Dear All It all depends on the insulation! The whole idea and purpose of the cavity is to prevent water going from outer to inner leaf. So.....any form of insulation that bridges this permanently in such a manner that water can get thru is not appropriate. Ideally, as with most building alterations, it is best to be reversible i.e. you can suck out the insulation as in beading or rockwool blown fibres etc as opposed to PU foam or the like which sets and that is it! In other words - chose the right product and application method and its fine to do Chris

[Tony]

At first it was a builder friend who, whilst discussing a damp patch which was high up on a bedroom wall, explained that it was likely to be debris bridging the cavity and allowing water to cross. He added thats a reason why cavity wall insulation can cause damp problems. Since then I have heard that more modern fill materials do not cause the same problems, but when I contacted a firm with a view to getting the cavity filled, they were not interested because of the age/construction of the house.

Looking on the website of an UFH supplier, stone is apparently an excellent medium for heat transfer, about the same as the screed over the pipes. They recomend 60 to 100mm of thickness above the pipe and I would guess the flags are 50 to 75mm thick. I have to lift the flags for levelling, so while they are up I can dig out

150mm or so, to lay hardcore, insulation, UFH pipes and screed, before re-laying the flags on what will have to be a continuous layer of cement rather than spotting, to avoid cold areas. I have thought about the warm-up time and might have to use a night set-back control to drop the temperature a few degrees without cooling down completely. Cheers, Tony.

[George (dicegeorge)]

my house just has slates, no felt, so there's always gonna be some water coming in.

In such a situation the dry gap between the 2 walls to me seems to be of more use letting the damp drip down the inside of the outside than filling it with insulation along which the damp could get...

my distant cousins log cabin in finland was very watertight with 3 layers of kingspan/celotax, and triple glazing..

[Clot]

I share your concern. In our previous house, I had blown in mica which did not cause a problem. Our current house which had blown in rockwool from new did have problems with bridging, but whether that was due to initial construction I'm unsure (was not able to be about when the issues were resolved). The issue to me with blown in stuff is the collapse that occurs when one wishes to make adjustments such as putting in a vent for a clothes dryer or new gas boiler.