Blimey, just use glue!

Oh right, sounds good. How does it seal around the fixing then?

So you have a strip along each line of fixings along an edge?

As I said above, I don't trust glue if it sets hard, but then I don't understand the physics Tom is talking about regarding stiffness of the structure, so maybe that's distrust out of ignorance.

Still wondering about Orcon F, but I guess £££.

Where/how long have you been saving up that quote, to use, ST? Not from this topic. I doubt gravelld even meant what you make it look.

Posted By: gravelldHow does it seal around the fixing then?

I'd suggest getting hold of a bit and having a go.

Well, I guess to answer one of the questions about longevity is to test it - that could be in a lab or it could be to take something like Tom's ridged, screwed and glued monocoque designs and test it say 10 years in - and again in 20 years - at some point we could, with some authority conclude that either we are putting his PII insurer on notice or that he's cracked airtightness at a stroke

To answer another question - there has to be a design life - it may well be that we use the building beyond that, but no designer will sign up to a product with an infinite lifespan

Any architect putting an infinite life on a building is either so old they'll be dead before any problems arise, is so reckless that they are probably uninsurable or so stupid as to be not worth employing

As I said, for other than very small buildings I'd not be missing out on expansion joints. FWIW, I've seen air tests run in something akin to a hot box where OSB is correctly installed to studs with a 3mm expansion joint and we've then proceeded to put some pretty big fans into one half to measure leakage rates - it was actually pretty impressive - more than adequate to combat a 500Pa overpressure and to maintain a specific gas concentration on the test side - it did improve when the stud was tacked with 3mm closed cell foam and then the sheet material nailed on (ring shanks and air nailer) the improvement was actually that spectacular however- these were "proof tests" we did for a PFI school building (that was likely to be replicated in a number of locations with different "outer claddings"

Regards

Barney

One issue we have in the UK, is that given each home is owned by a different person, but they are all joint together, we don’t have a system that lets us rebuild them. In the USA homes are designed for 60 years and rebuilt after that time, but they mostly live in large plots in detached homes.

60 years most certainly couldn't be classed as "temporary" could it - whilst I do very little housing work, I did a project for social housing a little while back that had about a 40 year life set by the client - they really did want cheap, but reasonably well performing

Yes, we did both overpressure and under pressure - OSB nailed with full head ring shanks and at the correct centres (which are often tighter than your average installer imagines) showed no hint of moving at 500Pa positive and negative (for the actual application, there can be significant underpressure during the gas release cycle)

If the studs are going to move about then most certainly nailing into a resilient bed would outperform any rigid sticky stuff - it only has to move once and it's "gone" as a seal

I think my point however was that well nailed OSB with adequate bearing onto the stud (which could of course be metal with screw fixings) performed remarkably well at 500Pa - which is probably a lot more than local wind pressures. I would suspect that interfaces between elements are the weak points in reality - doors and windows to walls, walls to roofs etc. The test box did actually show a dramatic fail when we lost a short section of silicone mastic between the panels and the enclosure - it was very short section at a corner, not intended to be part of the test, but when it failed, it totally dominated the leakage - it had just shrunk back a little from the box, rather than the OSB

Regards

Barney

Posted By: Ed DaviesThat's almost worth remembering: 100 km/h wind gives 500 Pa pressure.

Had a few days of them recently.

Posted By: djh
Just out of interest I went looking and according tohttp://www.siga.ch/en/company/company-history.html" rel="nofollow" >http://www.siga.ch/en/company/company-history.htmlRissan was launched in 1994 followed by Sicrall in 1997. So they've been around for over twenty years - I wonder if any independent tests have been done of the first installations?

I thought I read/heard recently they had opened up one/some of the original Passivhauses and found them in good nick? But not sure if they used tape or not...