Russell griffiths Posted February 3, 2019 Share Posted February 3, 2019 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. 1 Link to comment Share on other sites More sharing options...
A_L Posted February 3, 2019 Share Posted February 3, 2019 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 1 Link to comment Share on other sites More sharing options...
Russell griffiths Posted February 3, 2019 Author Share Posted February 3, 2019 TBH I’ve picked the dearest option, I just put this up for others reference. Link to comment Share on other sites More sharing options...
ToughButterCup Posted February 3, 2019 Share Posted February 3, 2019 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. Link to comment Share on other sites More sharing options...
Russell griffiths Posted February 3, 2019 Author Share Posted February 3, 2019 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. 1 Link to comment Share on other sites More sharing options...
bissoejosh Posted February 4, 2019 Share Posted February 4, 2019 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. 1 Link to comment Share on other sites More sharing options...
Cpd Posted February 4, 2019 Share Posted February 4, 2019 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 Link to comment Share on other sites More sharing options...
bissoejosh Posted February 4, 2019 Share Posted February 4, 2019 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! 1 Link to comment Share on other sites More sharing options...
Cpd Posted February 4, 2019 Share Posted February 4, 2019 Thanks for the explanation ? I will be replacing my failed membrane this summer. Link to comment Share on other sites More sharing options...
scottishjohn Posted February 4, 2019 Share Posted February 4, 2019 (edited) 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 Link to comment Share on other sites More sharing options...
bissoejosh Posted February 4, 2019 Share Posted February 4, 2019 (edited) 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 Link to comment Share on other sites More sharing options...
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