I intend to insulate a room built in the 30's. This is an outbuilding/toilet that later was reattached to the house. It is 1.7m x 1m with solid brick but single layer. I have insulated the flat roof with 20cm of insulation but the walls are extremely cold. The walls have been tanked. I have bought insulated plasterboard GTEC thermal PIR board 50mm and wondering if this will be enough. The room is small and will have a little 400w electric radiator and don't want to reduce too much the size of the room.
50mm? Yep - that will transform the room. When you think about it, if you doubled this insulation thickness to 80mm, the extra improvement would be - ooh - 5 or 10% tops? 'Cos the first 40mm will have made such a huge difference, that there is relatively little heat still getting through for the 'second' layer to stop.
What about your floor? Ok, this is the least important area to insulate, but still worth doing if there's nothing there. All it would need, tho', is say 50mm Jablite - cheap expanded polystyrene foam stuff - with your flooring on top. Or even less.
Thanks, that's reassuring. I didn't want to have the plasterboard in place, set some units and find out months later it wasn't enough. By the way, can you dot and dab insulated plasterboard. I don't want to drill through the tanked wall too low where I was getting some damp, which has been sorted now.
I understand you can dot and dab these boards on. You would normally use a few mechanical fixings too 'cos if there's a fire the boards will come down! If I were you, fixing this in a small bathroom, I wouldn't bother with fixings, just adhesive. I think I'd also be inclined to use cartridge-type adhesives such as StixAll or Sikaflex - really powerful, completely water-resistant and with excellent 'grab'. Your floor will be bludy cold - but only if you walk on it...
I like the idea of insulating the floor. I could replace the 15mm of flexible self levelling with 25mm jablite. How would I tile on top, just straight with tile adhesive?
Wouldn't think you can tile straight onto the jab boards - can't see the adhesive bonding to the polystyrene Maybe cover the jab with 12 mm tile backer board then your ready to tile With floors you need to eliminate any flex or your going to end up with either loose and/or cracked tiles. Not sure of the compressive strength of the jab boards used in this situation but as they're going over a solid floor, may be ok.
As Dave says, tiles need a solid base to be fixed down to. I know you can get flexible tile cement and grout for when laid on floors with some flex like floorboards, but you really need to eliminate movement as much as possible. Don't really know what to advise - sorry. Certainly, to remove any flex your own idea of self-level will be the best, but I'd be concerned about just how cold this tiled surface will be - I have one myself, tiled on to the concrete base. Chilly... Perhaps post this on the tiler's forum to see if there's some way of adding insulation without movement? (There is one, isn't there...)
There used to be a couple of tillers on the forum I seem to remember but that was some time ago Seems like a regular core of forum members that ask questions or answer some (or both) but not many stick around for any length of time Or when the regulars get a bit upset with someone, or the on-line sparing gets a bit too much, they throw their toys out of the pram and storm off - never to return Or......maybe they just lead a more interesting life than me and the SF Forum is way way down on the list of life's priorities Anyway; Jablite 12mm tile backer screwed down Tile (flexi ady and grout as DA mentioned) - Good quality stuff as well, powdered for both and certainly not a bucket of combined ady and grout all in one muck Nice warm floor
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