hi all

[ners]

hi everyone, joined up the other day and just wanted to introduce myself. I have been in roofing for around 30 years, mostly as a slater/tiler but also teaching slating/tiling for nvq's. I now work for a roofing merchants where i am the internet sales manager/ technical adviser. Feel free to ask any questions anytime regarding products, prices or workmanship, my details are on my profile. Not here to spam for sales but to offer genuine advice when needed.
Graeme

 

[^woody^]

 

[catlad]

Well I am rained off early today so there are some perks to working in an office I guess although I don't think I could do it. welcome to the site

 

[ners]

Thanks all,
Must admit, working office based is soooo much harder than being on the tools. they make me stay till 5pm every day!!!!!!

 

[hardmetalking]

Hi wonder if you could help me?
I have a roof to do on a new swimming pool. I need 142m2 of foamglas to a total depth of 200mm plus 30 tins of pc56 all to be delivered next week......do you know any suppliers that could help me out?
My other query is I also have 22m2 of flat roof on the same swimming pool, is there a standard roof build up for single ply membrane or can you install directly onto foamglas? The architect has specified 125mm insulation but this doesn't seem up to the job? Not compared to 200mm foamglas.
Any thoughts? Cheers.

 

[ners]

Howdy, will take a look at this when I am back in the office tomorrow.
Which single ply are you using. Pvc, tpo or epdm?

 

[hardmetalking]

Sarnafil was specified but I'm happy to use any other top brand that comes with a lengthy guarantee

 

[AlphaTeamBuilder]

Hi there.

You can buy PIR insulation with hard facers (ply or grp) to glue or fix your single ply membrane to. however, i dont like using them so when we do a flat roof we would install PIR insulation and overlay with 18mm tongue and groove OSB3 which we would fix with extra long screws at a rate of 6 per sheet. This provides a perfect substrate for our preferred single ply (EPDM) to be fully adhered to.

 

[catlad]

I think full metal jacket will scorn a mere 50yrs.

 

[ners]

Could not get any info on foamglass at all from my usual insulation suppliers. Have to agree with Alpha though, his spec is what we normally see

 

[hardmetalking]

Surely there is thermal transfer through the long screws creating cold spots?? As I've said before where is the vapour control layer or ventilation in single ply membrane roofs??

 

[ners]

Last build up i used was osb, then vcl (torch on underlay), then foil board insulation, more boards then epdm.
What about using an insulation board faced with ply, and adhering that to the vcl. some spray pu adhesive would normally do that

 

[hardmetalking]

This is an indoor heated swimming pool with lots of glass, it has to be a top notch roof hence why 90% is 200mm foamglas with zinc on top. I'm going to try and persuade the client to change the single ply to zinc as I can't find anyone who knows the correct build up. Thanks for your help anyway.

 

[AlphaTeamBuilder]

Surely there is thermal transfer through the long screws creating cold spots?? As I've said before where is the vapour control layer or ventilation in single ply membrane roofs??

You're right. There is some cold bridging along the length of the screws. I've looked into this in the past and didn't really find any super solution. I did come across helical twisty nails which (apparently) if made from stainless steel, have a lower thermal transfer rate. It is advised to only fix as many screws as necessary to meet wind up lift requirements thus reducing the cold bridging.

The foil facers on PIR insulation can work as a vcl but in an area of very high humidity such as a commercial kitchen or a swimming pool I would be inclined to specify a specialised ceiling which incorporated its own vcl.

The other option is to ventilate the void and install insulation between and under the ceiling but again you will still get a certain amount of cold bridging.

 

[Xenon]

You use thermal sleeves for fixing insulation under single ply.

They have specified Foamglass because of its compressive strength. It negates the need for a ply deck. However, there are issues bonding a single ply to Foamglass, it will need to be a mechanically fixed system.

You do not mention dew point calcs for swimming pool or ventilation requirements. Internal ceiling will be critical to these calcs too. A minimum will see a foil lined vapour barrier. Foamglass is available from SIG, and the cost will make you cry. We usually only use it under Asphalt .