Can anyone give me an idea of what sort of price I would pay for
100* 1.2*2.4*100mm sheets of polystyrene?Or, what is the typical discount over 1. Where would I be looking, builders merchants, or are there specialist suppliers that do insulation?
Builders merchants will give you a price but flick through yellow pages and look for packaging suppliers who do poly boxes etc. My B-i-L does everything in poly and can probably do sheets at a decent price, I'll ask if you want?
I have recently being paying about £8 per sheet (8'x4') for the 50mm jablite! I would guess that double the tickness may mean double the price.
What are you using it for, most specifications are now requiring the horrably expensive urethane boards!
I suspect I'm quite far away, Fife, Scotland.
I'm being stupid. B-i-L ?
If you buy slight reject boards
Everyone I know who has asked for quotes from them has only been offered first class non-seconds boards at about the going rate.
Sam
Brother-in-Law... I may see him tomorrow, I'll ask if he has any contacts in your area.
The tiles+battens+tar-paper on the roof of this house need replaced. The boards beneath are sound.
I was considering replacing the tar-paper with 100mm polystyrene. (with minor alterations to other stuff)
To create a warm roof, to enable the use of the attic as habitable space at some point in the future.
The extra work is not that great, at this point.
Hmm. Got a whole lorry load from them a year ago at about half the going rate and need some more soon. I'll see what happens.
Ah. I was getting hung up on assuming the first word was Build-something. Many thanks.
I guess it's because they get stuff in fits and starts and the people I know were just unlucky.
Sam
In article , Ian Stirling writes
Do you lay roofing felt on top of the polystyrene as well, or just tile straight on top?
Specialist insulation suppliers will be 20-25% cheaper than most BM's.
I think those sheets are about a fiver retail, so maybe 3 quid trade? Can't remember.
An 8' x 4' sheet of polystyrene, 50 mm thick cost about £18 last week at Jewsons. If cost per unit volume is similar, then double this thickness would be £36 !! Can't believe that either !!
Nick
That's a problem.
If you could figure out the attachment of the battens securely (no more nails?) then it might be an option to just tile straight on top of it, if you can be sure that you've got the battens secure.
Simply cutting grooves for the tiles to fit in with a circular saw might be an option with higher density foam.
Glue on a sheet of polystyrene, with battens pre-fixed, put the tiles on from below, and repeat until finished.
However, subsequent work on the roof would be interesting, as you'd practically require crawl-boards, and the risk of tearing a batten off the polystyrene is probably fairly high.
I suspect sheets of 4mm exterior grade ply, with the battens fixed to that may be an answer.
Vertical strips of wood under tar-paper, with the battens fixed to them may be a better one.
Is there a better barrier than tar-paper?
Still at the early stages, just wondering if it's practical at the moment. I don't see any show-stoppers.
First thing I'm doing is attaching ropes to the rafters, going through near the top., as an extra backup.
I'm confident I could do it without, but I've been confident before. Looking silly dangling at the end of a rope beats looking silly while falling through the air.
Though the eaves are only 3-5m off the ground that's about 2.5-4.5m further than I like to fall.
Wise words.
:-)
Mary
You don't want horizontal battens fixed to a solid roof. Any water that gets through the primary covering (tiles, slates WHY) will be trapped along the top edge of the battens and hasten the rot of their rot.
On a boarded out roof you put the sarking on first, then vertical battens and horizontals ones for the tiles on top. The verticals give space for any penetrating water to run down and out into the gutter.
And what are you going to nail then to? No nails and the first decent blow will have the lot off...
Try the "gortex for houses" the name of which slips my mind ATM. It's expensive but does breath unlike traditional felts and tar paper and doesn't perish/rot either.
True, I wasn't really thinking.
The battens on my roof have pretty much lost it. I have serious doubts that they were treated wood, and debris has built up (birds are partly to blame) to such a level that they are almost buried...
Or in my case, a handy gutter of tar-paper that holds the water against the boards.
Cowboys.
There are no nails on the tiles on my roof.
The tiles sit on the battens, and have a little peg that holds them on. Seems to work mostly OK. A few have fallen off, but only where the batten is pretty much rotted through, and the tile has pulled the corner of the wood off.
Doesn't seem anything that would inherently stop it working if it was just cut into the polystyrene, though the common insulating grade is not dense enough. (I suppose tiles sitting in pools of water would not be good).
I was assuming breathing would be pretty much irrelevant, if it was on the top of thick insulation. The idea was basically to protect the verticals, which would be glued onto the polystyrene from water. Then again, if water did get in, being breathable would be a good idea. I have to think about the fixing a bit more.
Trying to decide if attempting to keep the polystyrene as an entire skin, glued on with foam, which could be a very watertight layer, or penetrating it with hundreds of fixings is better.
I wonder if simply attaching the verticals at the top and bottom would be adequate, to carry the tension loads.
I need to do more research on adhesion of stuff to polystyrene in the damp after many years.
Thanks for the comments.
Hi,
CW Berry are quite cheap for 100mm at £12.12+
cheers, Pete.
Tyvek for one, or breathable roofing underlay for the generics.
The pdf's by Knauf give a clear overview of fixing and layering details. I would think that mechanical fixing overlayed with a breather membrane would be quicker, easier, and more likely to keep a BCO happy. Counter battens nailed through the breather & insulation into the rafters using spiral fixings, and tiling battens on top. Vapour barrier on the inside. Knauf
An alternate to the poly sheets especially if you are keen on a warm roof and are going to strip it anyway is the Airtec film from YBS, now stocked by Screwfix (and others). It's equivalent to 50mm poly, can be fitted to give a
0.35 U value and so so simple to fit. Inner layer doubles as vapour barrier when taped.HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.