how do i internally insulate

delta1980

hi im doing a renovation on my house and was wondering if anyone can tell me the process of internally insulating my house. ie

1) what type of insulation board to use. thickness, what product do i use, etc

2) do i fix it directly onto the wall or do i build a floating wall out an inch or two from it

3) Do i need some type of breathable membrane

Ceiling need replacing - Q. would it be cost effective to use insulated plaster board

antiskeptic

delta1980 wrote: »

hi im doing a renovation on my house and was wondering if anyone can tell me the process of internally insulating my house. ie

1) what type of insulation board to use. thickness, what product do i use, etc

Kingspan Thermawall is one such - you can get specs online. You'll unlikely be able to reach optimal thicknesses (i.e. as specified for a new build) with such products since they a) are only made up to certain thicknesses and b) will take up significant amount of room volume even at modest thicknesses.

In a recent job, I used 50mm board (12mm plasterboard + 38mm insulation) on the walls and ca. 80mm board on the ceiling. This turned an icebox into a comfortable room.

Consider using insulated plasterboard on (some) internal walls if they're brick/concrete since such walls act as giant icecubes 'sucking' heat from the air and leaking it down to ground

2) do i fix it directly onto the wall or do i build a floating wall out an inch or two from it

I fixed direct to the (concrete) wall using hammer-in mushrooms. On an 8x4 sheet I used 12 fixings (3 across the 4ft and 4 down the 8 ft) They're an excellent fixing. Buy a cheap rotary hammer type drill to make short work of the hole drilling.

If the wall is undulating badly, consider sticking fillers (6" square pieces of plain plasterboard, thin pieces of plywood?) at the points where the mushrooms will go, first. Otherwise you'll cause the plasterboard to follow the undulations and mess things up a bit.

If attaching to a wood frame wall, use purpose-made plasterboard screws (which come in various lengths to accomodate insulation thickness). These screws are coated to prevent the water used in skimcoat rusting the heads - which can then appear through your paint.

3) Do i need some type of breathable membrane

Kingspan comes with a vapour barrier built in so I wouldn't add anything else. The issue is vapour travelling from inside the house and condensing on the cold wall - the vapour barrier would block this - not vapour from outside coming in. The plasterboard will breath on one side of the built in membrane and the wall will breathe on the other.

Or so it seems to me

Ceiling need replacing - Q. would it be cost effective to use insulated plaster board

Compared to what?

Most folk want to utilise their attic - which limits the amount of insulation you can easily install to that which will fit between the ceiling joists (then battening and flooring the attic space). Since ceiling insulation (and I'm assuming this is the ceiling under the attic) gives the greatest return-on-investment it would be worth spending the few extra bob on insulated plasterboard in addition to what's going in the attic.

Beware adding too much insulation to the underside of the ceiling - unless you've generous head height. Otherwise you'll make the room seem very cramped. I took off the aforementioned 80 from a 3.3m (at peak) ceiling and it made a noticeable difference. Do the same in a standard house and you'd turn the room into a cave.

delta1980

thanks for the info antisckptic,

does anyone know who does the cheapest insulation

hamish262001

delta1980 wrote: »

thanks for the info antisckptic,

does anyone know who does the cheapest insulation

work out how many boards you need and email all the building providers with the full list and you will get much better than asking for a price on a single board

I got mine at trade price

brendankelly

It depends on what type of walls you now have. If you have a working cavity block wall dry lining is the cheapest option but if your walls are stone you should read http://www.josephlittlearchitects.com/papers.html before you dry line.

St. Leibowitz

brendankelly wrote: »

It depends on what type of walls you now have. If you have a working cavity block wall dry lining is the cheapest option but if your walls are stone you should read http://www.josephlittlearchitects.com/papers.html before you dry line.

Alot of papers there. What (or which) specifically are you referring to ??

CBYR1983

delta1980 wrote: »

thanks for the info antisckptic,

does anyone know who does the cheapest insulation

U value in blanch were cheapest when I was buying boards recently.

Absolutely no affiliation.

brendankelly

St. Leibowitz wrote: »

Alot of papers there. What (or which) specifically are you referring to ??

I agree there is a lot of heavy reading in it. Braking the mould is one article and it is about how mould, mushrooms and all sorts thrive behind dry lining. It is a bit to heavy for my night time reading but I have seen first hand what grows behind drylining.