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Posted By: bot de pailleMy understanding is that the leaks came from the innovative rainwater harvesting system that was installed which uses the roof to store the rain water, doing away with the need for storage tanks.
Posted By: joe90This is a comment on this forum from an air tightness tester regarding OSB:-
I've never felt anything coming through the surface of OSB even at -100Pa decompression, the problem usually lies with the joins, junctions, angles and edges, as it does with any sheet material without a membrane behind it. If I were feeling paranoid about future performance, I'd slap a coat of PVA on it!
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Posted By: an02ew any counter batten that would nail through OSB
Posted By: Mike Georgewhere there is air leakage at the join this will reduce the air pressure on the rest of the OSBDon't think so Mike - he's surely talking maintained decompression.
I've never felt anything coming through the surface of OSB even at -100Pa decompression,5 m³/(m²·h) at 50 Pa (ie, about the building regs limit of airtightness) might result in about 18 m/h (or 5 mm/s) at 100 Pa. I make that force 0.03295 on the Beaufort scale ;-) I really doubt you'd feel it.
Posted By: joe90But, if the air tester is maintaining a decompression at a particular rate then surely the pressure is still on the OSB?. the fan will be running to make up for the losses at leaks.!!!!!
Posted By: Mike GeorgeDon't forget the purpose of a pressure test is to measure what leaks at a given pressure. If the blower/fan were to compensate for any holes in the fabric it would not be measuring what has been lost through the holes.
Therefore it does not compensate and as such if there are holes in the fabric however small then the air path through these is easier than through the fabric.
Posted By: joe90I've never felt anything coming through the surface of OSB even at -100Pa decompression
Posted By: djhPosted By: Mike GeorgeDon't forget the purpose of a pressure test is to measure what leaks at a given pressure. If the blower/fan were to compensate for any holes in the fabric it would not be measuring what has been lost through the holes.
Therefore it does not compensate and as such if there are holes in the fabric however small then the air path through these is easier than through the fabric.
Eh? The pressure test is at a defined pressure. If there are leaks then the fan has to work harder to maintain that pressure. So most definitely if there are leaks the blower compensates for the leaks in order to achieve the defined pressure!
That's why airtightness testers want an estimate of your airtightness, so they can estimate the size of fan required to achive the specified pressure. One tester I talked to couldn't test my house because all his fans were too powerful - designed for bigger, leakier buildings.
Posted By: an02ewif you were contracted to guarantee PH levels of air tightness, would you spec OSB as your air tightness layer without any other covering??????????Peter Warm
Posted By: fostertomtaaraa!
Posted By: fostertomPeter Warm
http://www.peterwarm.co.uk/certify
would, it seems - that has to be significant - from the horses mouth.
Posted By: ringiYes, but I would design a fail safe system that could be installed if the first test failed with just the OSB.
Posted By: an02ewPosted By: ringiYes, but I would design a fail safe system that could be installed if the first test failed with just the OSB.
then ,no to OSB alone? so what about if the goal post were moved a bit, say .8 or .9 ac/h would you guarantee that with OSB?
Posted By: bot de pailleIf you already thinking of a plan B, seems plan A should be avoided.
Posted By: bot de pailleIf you already thinking of a plan B, seems plan A should be avoided.Wouldn't get to the moon that way! This is leading edge stuff, always needs a plan B.
Posted By: Gotanewlifebut can't help thinking this is quick and easy to test adequately, qualitatively.