Reroof: Best Membrane?

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Hi all,

I’ve asked about roofing membrane on here before (thank you one and all!), but have a few further questions.

I had planned on using Tyvek Supro… but I’ve just noticed that everywhere states it is “water resistant”. Huh?! Not waterproof?

Found one person who was in the middle of a reroof. Membrane and battens were down. But only half tiles. Water leaked through the Tyvek.

Is Tyvek Supro waterproof or not? Was under the impression that it was completely waterproof, and once it’s all on the roof, the roof is watertight… and you can take your sweet time to tile!

If it isn’t waterproof, what is?!

Thanks!

stuart45

It's a breather membrane that's water resistant, not proof. It's good enough to go under tiles, but if used solely as a water barrier would allow a small amount of water through in time.

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stuart45 said:

It's a breather membrane that's water resistant, not proof. It's good enough to go under tiles, but if used solely as a water barrier would allow a small amount of water through in time.

Hmm. That begs the question then, if, what is the point of a membrane?

I understand one function is to stop the uplift of tiles in heavy winds.

stuart45

It's still a secondary barrier if some water or snow gets blown under the tiles. Water resistant means that very little rain would get through if the membrane was left exposed to heavy rain for days on end.

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stuart45 said:

It's still a secondary barrier if some water or snow gets blown under the tiles. Water resistant means that very little rain would get through if the membrane was left exposed to heavy rain for days on end.

Okay, that’s must more reassuring! Thanks!

Doozergirl

I think with a lot of membranes you cannot leave them on and take your time with tiling as they degrade in direct UV exposure.  IIRC, our roofer said three weeks is about the maximum. 

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Doozergirl said:

I think with a lot of membranes you cannot leave them on and take your time with tiling as they degrade in direct UV exposure.  IIRC, our roofer said three weeks is about the maximum. 

Seems the majority of membranes state a maximum of 4 months.

Frankly though, I wouldn’t hang about and take a few weeks off. I’d get cracking on the tiles. But, if a downpour was the next day, prior to tiles being laid, I’d like to know it was completely watertight!

Klober Perno Forte seems like a very good contender.

Doozergirl

laurencewhymark said:

Doozergirl said:

I think with a lot of membranes you cannot leave them on and take your time with tiling as they degrade in direct UV exposure.  IIRC, our roofer said three weeks is about the maximum. 

Seems the majority of membranes state a maximum of 4 months.

Frankly though, I wouldn’t hang about and take a few weeks off. I’d get cracking on the tiles. But, if a downpour was the next day, prior to tiles being laid, I’d like to know it was completely watertight!

Klober Perno Forte seems like a very good contender.

Oh yes, well rain happens to roofers too!  The membrane would be worthless in this country if you had to do it that quickly. 

The house next door to us, being built by a developer had it exposed for months on end...

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Doozergirl said:

laurencewhymark said:

Doozergirl said:

I think with a lot of membranes you cannot leave them on and take your time with tiling as they degrade in direct UV exposure.  IIRC, our roofer said three weeks is about the maximum. 

Seems the majority of membranes state a maximum of 4 months.

Frankly though, I wouldn’t hang about and take a few weeks off. I’d get cracking on the tiles. But, if a downpour was the next day, prior to tiles being laid, I’d like to know it was completely watertight!

Klober Perno Forte seems like a very good contender.

Oh yes, well rain happens to roofers too!  The membrane would be worthless in this country if you had to do it that quickly. 

The house next door to us, being built by a developer had it exposed for months on end...

Well that was my thinking too!

There’s a house just down the road from us which felted (well, membraned) and battened… but no tiles. Been like that for a good 6 months, if not more!

stuart45

Damage by UV light starts as soon as it goes.on the roof, so the quicker it's covered the better. When they say 4 months it doesn't mean that it's perfect up to that time, and then suddenly degrades. Even when covered it goes in time, especially at the eaves.
Waterproof and resistant is.like.outdoor clothing. The old oilskins were waterproof, but not breathable. Modern ones are more breathable but aren't quite as waterproof.
When a product is said to be breathable there are different levels of breathability which can be confusing to people, as some hardly breath at all.
With clothing the ratings are much clearer and easy to understand.

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stuart45 said:

Damage by UV light starts as soon as it goes.on the roof, so the quicker it's covered the better. When they say 4 months it doesn't mean that it's perfect up to that time, and then suddenly degrades. Even when covered it goes in time, especially at the eaves.
Waterproof and resistant is.like.outdoor clothing. The old oilskins were waterproof, but not breathable. Modern ones are more breathable but aren't quite as waterproof.
When a product is said to be breathable there are different levels of breathability which can be confusing to people, as some hardly breath at all.
With clothing the ratings are much clearer and easy to understand.

Goes at the eaves first, that’s for sure. I’m planning to use eaves support trays, to hopefully help prevent that early death!

There are certainly different levels of breathability and waterproof ratings… both of which confuse me! I’m used to seeing a hydrostatic head rating on outdoor clothing, so these membranes confuse me a little!

The top three contenders seem to be…

Tyvek Supro

Klober Permo Forte

Procter Roofshield

All about the same price really, so it all comes down to performance.

Our roof is 30 degree pitch, with Redland 49s. In a coastal area. Our house is backed onto a field too.

Klober Permo Forte seems to be “advertised” as the strongest out there.

Surely there is a one go-to membrane that all roofers can agree on?