Celotex prices

[^woody^]

Is the proper spray in stuff the same as what's inside the boards?

They both contain isocyanate and polyol so more or less, yes. You will just need a can of silver paint too.

 

[Ian H]

And some Kingspan stickers?

 

[^woody^]

Blue bingo pen

 

[JP_]

We are getting a lot from Poland at the moment.
It's only £400 shipping for a 32ton artic and the insulation(and building products) over there is a lot cheaper.

Who do you order from?

 

[Ian H]

Would anyone buy 1200x200 pieces of 100mm to fill rafters with 400mm centres?

Price would be equivalent to £20 for an 8x4 piece.

 

[cjard]

What dimension are the rafters?

 

[Ian H]

5x2's and 8x2's

 

[John D v2.0]

Is the proper spray in stuff the same as what's inside the boards?

No, the proper stuff is made in a factory and has consistent, optimal sized bubbles. On site is never going to be able to compete reliably. If it were cheaper they'd just use the same in the factory.
On site would have better air tightness though when sprayed on joists etc.

 

[oldbutnotdead]

Would anyone buy 1200x200 pieces of 100mm to fill rafters with 400mm centres?

Price would be equivalent to £20 for an 8x4 piece.

Probably- do your wastage suns though, 400 centres = 350 gaps to fill, if I was doing it I'd be cutting 3 x 350 x 200 from one 1200 x 200 so there's 20% waste there to start with.

 

[^woody^]

No, the proper stuff is made in a factory and has consistent, optimal sized bubbles. On site is never going to be able to compete reliably. If it were cheaper they'd just use the same in the factory.
On site would have better air tightness though when sprayed on joists etc.

I'm not sure about the supply of optimal bubbles, but the point was that the supposed cause of the celotex price increase is low supply of a chemical to make it. But tins of spray foam which is the same stuff (except bubbles) have not increased in price.

 

[John D v2.0]

I'm not sure about the supply of optimal bubbles, but the point was that the supposed cause of the celotex price increase is low supply of a chemical to make it. But tins of spray foam which is the same stuff (except bubbles) have not increased in price.

Ah right i didn't realise Ian was meaning regarding the price of tins in reply to you, I thought he meant some professional equipment. But if not, good point, perhaps the MDI is a significant proportion of the cost of a full board, but for the c the MDI cost increase can be absorbed easily?

Regarding tins, according to soudal my tin at about a tenner Coverage wise, the 750ml can offers a box yield of approx. 30L, so 330 pounds a metre cubed (and 0.0345 lambda)
Whereas a rigid board is about 200 pounds a metre cubed and around 0.021 lambda.

 

[Ian H]

I don't mean tins, unless this guy is linked up to 334 tins from Toolstation

 

[cjard]

That's probably icynene or similar, not the same stuff as kingspan (PIR), and not the same stuff as in the soudal cans (PUR, and not consistent in its structure). Spray foams do well because they fill gaps well. There's a point beyond which it's senseless to focus on lambda and better to focus on air tightness so it's less important that a spray foam lambda is numerically greater than kingspan

For on site vs in factory PIR foams,I suppose it depends what is meant by "same" - It can be the same stuff, it can be bubbled differently, it can be better or worse thermally for reasons mentioned above, with a good chance that it will be better than an poor kingspan install, even though it may be worse lambda

Ian, if you're looking to fit 4 inch of kingspan between 5 inch rafters, why not use seconds? You've got an inch gap to absorb any ugliness in the sheet..

 

[Ian H]

I probably will use seconds. I'm keeping an eye on Gumtree and E-bay for anything local.

I saw the spray stuff at the Ideal Home Show and it did look good, only odd thing was that it closes any ventilation gap behind it.

 

[John D v2.0]

I probably will use seconds. I'm keeping an eye on Gumtree and E-bay for anything local.

I saw the spray stuff at the Ideal Home Show and it did look good, only odd thing was that it closes any ventilation gap behind it.

There are pros and cons of sealing things up so well. Pros are air tightness and good vapour control. Cons are if anything does become wet the ventilation of the timber won't be very good any more. Also if you change your mind good luck removing it.