The thread about insulation reminded me of a question our daughter asked a few days ago.
She asked me if there is an insulation that she can fit to her inner walls to help keep the cold out and the heat in during the colder months. She tells me that it has a foil backing. I have no knowledge of it at all.
Help please
Dave
Celotex or Kingspan. Both are made from polystyrene-based rigid foam with a foil vapour barrier/ heat reflecting layer. You can get it in various thicknesses from 10 to 50mm (and even thicker for loft use) but the most popular for your daughter's intended purpose is 25mm.
Standard sheet size is 2440 x 1220 mm, or 8 feet by 4 feet.
Celotex also make an insulated plasterboard which has 25mm foam/foil backing for a total thickness of about 38mm. The plasterboard has bevel edges to help obtain a smooth finish to joints.
Many thanks for that, I'll take a google and see what it will cost her.
Dave
No, Celotex is a PIR foam, polyisocyanurate.
Thanks Dave.
And to the best of my remembery Kingspan is also a polyurethane foam although Kingspan group do make some polystyrene based products as well.
I've done 50mm internal kingspan to three rooms (3 bed semi) with outside exposed solid (not cavity) walls and it's kind of made a difference to the comfort of the rooms retaining more heat while the boiler has turned off for the night and the outside (now) is freezing again.
However, I later found that some of that operation had also covered up some previous thinly covered ex-chimney places and also a drafty gap between the floor boards and the house walls; the cold air blowing into the gap from air bricks under the house. Guess I'm saying, look for stopping sources of drafts first before going mad on the insulation.
Internal insulation #1 - Room heats up very rapidly Only the mass of air in the room need be heated, however without objects of some thermal mass in the room it will lose heat relatively quickly if doors are opened.
#2 - Cold draughts off walls are eliminated This is most noticeable in areas such as hallways, rooms 2-3 outside walls like bathroom, boxrooms, kitchens etc.
Cavity wall insulation #1 - Room holds heat for longer You are heating the mass of the inner leaf bricks which takes many kW over many days, but the insulation prevents that heat leaking away so the fabric of the room holds heat for longer.
#2 - Cold draughts off walls are eliminated This is true, but more difficult to achieve in places such as hallways or bathrooms where heating is less so the inner leaf of bricks do not reach a particularly high temperature.
External wall insulation. As for cavity wall insulation, only even longer warmup countered by even larger thermal mass.
Internal insulation is very good for rarely used rooms & on-demand/ limited heating, because it permits a faster warmup by not having to heat n-tons of bricks to whatever-degrees-C. Conversely with cavity- wall & external insulation it is better to have a reasonable background temperature maintained 24/7 and boosted as necessary.
I know someone would say that. Polystyrene isn't PUR/PIR... PIR has a decent fire rating, polystyrene melts shown a candle let alone a building fire. B-)
We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Dave saying something like:
Google for Kingspan, Celotex, etc. Their sites contain all you need or ever want to know.
isnt polystyrene the white crumbly stuff which when it burns drops molten burning gobbets downwards, once used on bathroom ceilings?
kingspan and celotex dont burn so dangerously i think.
[g]Both PIR PUR PS foam all burn with toxic smoke unless a) fire retardant or b) covered in plasterboard which is itself 30min+ fire rated. You are dead within 2-3 minutes in a house fire from toxins released by furniture, carpets (wool), curtains, vinyl wallpaper. Same applies to Marmox - the tile/plaster & cement covering provide protection.
Plaster only fails with accelerant as a rule, so try to avoid keeping such chemicals in a house at all.
Thanks JS - useful summary to remember.
My own cottage - a stone built farmer worker's cottage in Scotland - had been up- graded in the 1920's with suspended wooden floors, and lathe and plaster on the 3 ft thick stone walls. They knew about ventilation but not insulation, and the house was probably colder than in it's original form as they allowed the under floor ventilation to run up the cavity between the plaster and the stone walls into the roof space. We would sit huddled round the coal fire with heat radiation in front and cold radiation behind !
I had to rip all the L and P off, insulate and then reclad the walls. The house has probably a characteristic now somewhere between cavity insulation and internal. The stone walls do act as a heat reservoir but rather long term.
Rob
Now that is thermal mass :-) Actually 910mm is substantial enough to have "some U-value".
Heh-heh, I know that well.
It will be, insulation is not perfect re reaching the thermal store. Internal insulation is great for "your body heat is enough".
We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "js.b1" saying something like:
Not much, at that. The heat will still be passing through it, as I've found in plenty of old farmhouses.
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