Roofing membrane

[Russell griffiths]

So the snow turned up, and being a soft southern sod I needed to find something to do that didn’t involve going outside. 

So 72 hours later there’s not a drop of water passed through either of these roof membranes. 

How else do I decide which one to use, both from the same manufacturer, difference in price between the two is roughly £300. 

Its not just @JSHarris who’s the scientist, can I have an OLOGY. 

[A_L]

29 minutes ago, Russell griffiths said:

How else do I decide which one to use

 

The manufacturer says Majcoat can be exposed for upto 8 weeks while Majcoat 150 can only be exposed for upto 4 weeks.........so

 

https://www.siga.swiss/global_en/catalog/majcoat

[Russell griffiths]

TBH I’ve picked the dearest option, I just put this up for others reference. 

[ToughButterCup]

37 minutes ago, Russell griffiths said:

[...]

How else do I decide which one to use,

[...]

 

Look at your cost-to-completion spreadsheet.

Put both numbers in. Decide whether the cost difference makes any material (sorry) difference.

[Russell griffiths]

Just now, recoveringacademic said:

 

Look at your cost-to-completion spreadsheet.

Put both numbers in. Decide whether the cost difference makes any material (sorry) difference.

Put them where, spread sheet ?????????

oh how I laughed, I’m a silly navvy not a mathematician 

 

membrane picked by trying to tear it apart, poking my finger through it, and how many free t shirts and knives the rep gave me. 

 

[bissoejosh]

Jet the hose at each of them, I did a lot of our walls with TF200 only to realise if the rain was driving it went right through but held water like your test no problem. I contacted the manufacturer who tested a swatch and confirmed it was as it should be and fit for purpose. I disagreed and replaced the lot with  a W1 class roofing membrane from Cromar which doesn't let a drop in.  Appreciate your membranes are roofing class but might be worth posting for others. 

[Cpd]

5 minutes ago, bissoejosh said:

W1 class roofing membrane from Cromar

Can you put a link to this product ? Not sure what the W1 part relates to. Thanks 

[bissoejosh]

It was Cromar vent 3 classic. 

 

https://cromarbuildingproducts.com/products/vent3-classic/

 

I used the Vent 3 pro

 

https://cromarbuildingproducts.com/products/vent3-pro/

 

on the roof after a recommendation on here and was really impressed with it. Roofs require a W1 class membrane which is basically how much water is allowed through. The TF200 I used was a W2 product which passes building regs on walls but as explained in driving rain water was getting through which I didn't like and which could be replicated with a surprisingly low jet from a hose. I appreciate that once cladding etc is on the walls won't have anywhere like the same exposure as they do during the build but I didn't like seeing droplets form on the inside where I had window openings and wet OSB behind! 

 

 

 

 

[Cpd]

Thanks for the explanation ? I will be replacing my failed membrane this summer.  

[scottishjohn]

1 hour ago, bissoejosh said:

Jet the hose at each of them, I did a lot of our walls with TF200 only to realise if the rain was driving it went right through but held water like your test no problem. I contacted the manufacturer who tested a swatch and confirmed it was as it should be and fit for purpose. I disagreed and replaced the lot with  a W1 class roofing membrane from Cromar which doesn't let a drop in.  Appreciate your membranes are roofing class but might be worth posting for others. 

JET HOSE !! that would be equivalent to a class 7 hurricane or worse --suspect you blew holes in or surface was badly rubbed

what was over the top of this membrane ?

left open to UV for too long before it was clad?  not meant to be subjected to direct sunlight  or it degrades

if atmospheric pressure is 14,7 psi --then even 2 bar from garden hose is higher pressure than you will ever see 

a jet wash will be 10-15 bar -- or at the bottom of sea 100 metres down 

so hardly a fair test 

 

Edited February 4, 2019 by scottishjohn

[bissoejosh]

Jet the hose - not Jet Hose. As in sprinkle the garden hose with a small amount of pressure, all I said was it was surprising how little pressure was needed.

 

I used a Garden hose to test after witnessing driving rain penetrating the membrane.

Edited February 4, 2019 by bissoejosh