Breathable membrane installation (Scotland)

[nostos156]

Hi,

Got a dormer window in a bay shape that needs work done to the roof framing of it, as the flashing on the sides has failed over the years as well as the mortar that sealed between the slates at the peaks. Will involve ripping the slates off and repairing any sarking/framing that requires it along with replacing flashing. At the same time, I figured putting down a breather membrane would be a decent idea while I'm at it, as due to the roof age, it's just bare slate nailed into the sarking boards.

Question is, can I get away with installing the membrane straight onto the sarking boards? Was thinking of using Cromar Vent3 Pro (I'm in climate region 4 for wind uplift) but all the installation instructions I look at when it comes to membranes always seem to just talk about using battens on top like how they do in England.

So, can I just staple/nail (which is preferable?) the membrane directly to the sarking boards, tape the laps as what seems to be required for my region, and then just nail the slates on top? Is that sufficient or will wind uplift still be a problem there?

Thanks.

[JohnMo]

1 hour ago, nostos156 said:

Cromar Vent3 Pro

I used this on my shed, not the best stuff.

 

Have a look at proctor roof shield 

 

1 hour ago, nostos156 said:

can I just staple/nail (which is preferable?) the membrane directly to the sarking boards

Yes, I just stapled

1 hour ago, nostos156 said:

, tape the laps as what seems to be required for my region, and then just nail the slates on top?

No need to tape with decent membrane.

 

Copper nail on top, if proper slates, if tiles batons are needed.

[scottishjohn]

and you could use this  to get over having to run 2 layers of slate on frist row whwich can make it bulky it slates are not consistant thickness

https://www.roofingsuperstore.co.uk/product/continuous-eaves-course-for-roofing-slate-pack-of-10.html?ppc_keyword=&msclkid=a7053c4218ad16b22acc5b570381f501&utm_source=bing&utm_medium=cpc&utm_campaign=Pitched Roofing - PLA&utm_term=4575823829934575&utm_content=GRP Strips, Troughs, Soakers

 goes over the membrane and backs up bottom row of slates 

you could use at top as well makes a nice job

Edited October 20 by scottishjohn

[nostos156]

5 hours ago, JohnMo said:

I used this on my shed, not the best stuff.

 

Have a look at proctor roof shield 

 

Yes, I just stapled

No need to tape with decent membrane.

 

Copper nail on top, if proper slates, if tiles batons are needed.

 

Proctor Roofshield is like 3x the cost of what I can get the Vent3Pro for. What was wrong with it? And yes, just reusing the proper old slates. Cost is a factor for this since the flashing I'm replacing I'm going with Ubiflex/IKO Lead-E as well since the cost of lead is atrocious these days.

 

I'm not redoing the whole roof, just the area above the dormer while I have access to it. Main reason would be to cut down on wind getting to that part of the roof since its the least insulated area of that room by nature of it being a dormer.

Edited October 20 by nostos156

[JohnMo]

17 minutes ago, nostos156 said:

Proctor Roofshield is like 3x the cost of what I can get the Vent3Pro for

Way better quality, nice and thick compared to paper thin.

[nostos156]

18 minutes ago, JohnMo said:

Way better quality, nice and thick compared to paper thin.

 

Was it the PRO version of Vent3 you used? The gsm figures for both are similar (proctor is 185, PRO is 165), but Vent3 has a light/classic etc version that is much thinner.

Edited October 20 by nostos156