Advice for sarnafil roof + Verge cement mix

[fluff48]

Hi there
We have lots of knowledgeable dibbers who are good for sharing advice, so hopefully someone can help.

We have sarnafil membrane on our wooden porch flat roof. If we get heavy rain hitting the house in a certain direction we get a lot of water coming through the roof where it meets the wall of the house.

Any ideas on where the water could be getting in? The seals for the membrane appears solid. Previous owners have cement above the up stand so I think I may need to fill in the gaps/renew any loose bits.

So I few things:
1) what cement mix should I use above the upstand?
2) is the split along the upstand a concern? It just seems to be a top coat. If so, is there a sarnafil specific mastic to use to seal?
3)what mix of cement do I use for the verge tiles? I’m assuming I should fill the gaps (last pic)

So pics below

Hopefully someone can help

[fluff48]

Does anyone have any idea on the cement mix I need? Cheers 👍

[Mr Tom Morrow]

Hi. Can you take some longer shots please so I can see the whole thing.

The first thing that's leaping out at me is there is no lead flashing. That will form a nice waterproof seal.
The tiles need to be stripped right off and replaced by new in my view.

[fluff48]

Thanks Mr Tom. I will try to get some more pics tomorrow.

I don’t think there is any lead flashing above the upstand, just cement. Both our porch and garage are like this. Our neighbour has a newer conversatory in uPVC with the same roof and no lead either. Not sure if it is supposed to be done like this🤔

Thanks for taking a look👍

[Mr Tom Morrow]

The problem with water ingress is that it's amazing how it can get into tiny cracks and even track slightly up if the wind is strong.

We had issues with cracked rendering and in the end had the whole front of the house re rendered. Problem solved.

Builders shy away from lead as it's expensive, plus it's not that easy to do a nice job.

I will await more pictures as that will give a better view - no pun intended.

[bernard301]

from a quick google there doesn't appear to be any obvious photos of any similar installations to yours.

It looks to me however like they have installed flush to the concrete and then rendered straight over, so you may get away with a standard cement mix (but would probably have to knock it all back and re-do as one rather than try and patch due to the extent of damage)

As for the split seam it looks to be more like a piece of beading however I would probably try and get in touch with a sarnafil specialist (or two) to gauge their opinion.

[colin39]

They use a dry verge system nowdays this is the one we used

m.ebay/itm/MANTHORPE-D...e-e13c64b09619

[fluff48]

Thanks for the replies guys. The weather hasn’t been great but grabbed these tonight, does this give the view you were looking for? Our neighbour has maybe a 2-3” beading above the upstand with cement over, but again no lead.

Would I be able to try taking out the cement above the upstand and refilling? If so what would I use as a cement mix?

If this doesn’t work then I probably need to get the experts in 😭😭😭

For the verge, the budget doesn’t stretch to renewing at the moment, so just looking for a cement mix to fill in the holes.
Cheers
Fluff

[Mr Tom Morrow]

OK. Cheap and cheerful job but don't hang your hat on it.
Get 2 tubes of translucent silicone so it dries clear. Mount the tube in a gun and gun it into all the cracks. Get a cheap glove to run your finger over it and ensure all the cracks are fully sealed.
That may give you 2 years of respite whilst you consider the way forward which is disc out a groove 5" above the roof and put a lead flashing in that will be similarly gunned with silicone where you disc the rendering out.

Any verges need ripping off and replaced with the new plastic products.

[fluff48]

Perfect, thank you. Silicone is my go to product so I’m ok with that (I never use a glove though, just wet my finger &#128563 but I didn’t want to spoil the sarnafil for others to try and fix later. 😀. The roof experts can do the lead part.

Now, I’m not keen on the plastic verges only because My last house had them and a tile blew off in heavy wind onto the car roof and popped the plastic verges off. It was because they were on with small nails, I suppose the right tradesman will fit them properly, just need to get a good one as my last good roofer has retired.

Thank you 👍