Sarnafil Help (and warning)

[gwwxxx]

I have a Sarnafil single ply roof installed on my recently completed extension by a professional installer who was sub-contracted by my builder.

After the bad weather in December (and once the snow had thawed) I had noticed that in a couple of small places the edging piece which goes from the last 6 inches of the roof edge over onto the vertical was starting lift off the membrane underneath.

I tried to contact my builder who didn't respond (not that surprising) so contacted Sarnafil who told me a guarantee had been issued and that I should contact the sub (they gave me the details).

Contacted the sub to be told my builder had never paid them and has since gone out of business. I had paid the builder in full months before. The sub is withholding the guarantee and wants me to pay for 50% of the roof again. Sarnafil are largely standing by their installer. Whilst I sympathise with them, their contract was not with me and I have honoured mine with the builder. I can't afford to pay for products twice.

So, can the small edges that have lifted be stuck back down? Is it a glue that is used, it looks like the edge was not properly adhered in a couple of places but I have no idea if this is DIY achievable or would require an expert.

I would rather do it my self it I can.

Any help appreciated!

 

[SurreyRoofingEstimator]

The Sarna is hot air welded at the joints so shouldn't actually part

The build up is the bottom layer of Sarna goes to the edge, the drip trim is then mech fixed through the 1st layer into a timber edging with a cover flashing strip welded to the top of the metal trim and then to the main field area (1st layer).

Is it the trim that has lifted from the 1st layer or the cover flashing that has lifted from the coated metal trim?

Is it def Sarnafil BTW

 

[freddiemercurystwin]

Your contract was with the builder not the roofer, it is him that you need to chase.

 

[SurreyRoofingEstimator]

Your contract was with the builder not the roofer, it is him that you need to chase.

Th OP would if they could but the builder is no more (more common problem nowadays of course)

 

[gwwxxx]

Thanks for the responses.

Its definitely Sarnafil, I have spoken with them and handily they have embossed their brand all over my roof!

I have attached a couple of snaps to show the issue, there are only three distinct places where this occurs and it doesn't look like a mechanical fastening.

I would dearly love to take this up with the builder, if we could have seen this coming we might have selected our contractor differently. I had no idea to think to protect ourselves against non payment to a sub.

Untitled

• gwwxxx
• 3 Mar 2011
• 1

Untitled

• gwwxxx
• 3 Mar 2011
• 1

 

[SurreyRoofingEstimator]

Looks like the hot air weld didn't take for some reason

What you could get done is a patch hot air welded over the lifted lap. Not the ideal situation but would at least cover the failed area, this shouldn't cost you a huge amount.

Best to get all the other welds laps tested with a seam tester (looks like a bent pointed screwdriver) just to check that is just a couple of isolated incidents and not endemic across the roof

 

[freddiemercurystwin]

Oh yea, when I scanned it earlier I thought the roofer had gone bust!

 

[gwwxxx]

Thanks for the info.

Just to understand the testing process, if I can lift the top piece and the bond breaks then I have a wider problem but if I cannot easily encourage the seam apart then the bond is secure?

I obviously don't want to cause further damage but if there are issues best confront them now.

Under what circumstances would hot welding failure be endemic?

Is there a bonding agent used or is it the PVC being melted to bond to its neighbour?

I am half thinking that the loose edge could be secure with a PVC glue - the type used to fix dinghys - horrific idea?

I really appreciate your input on this.

 

[Zeberdee]

Hi,

I've not worked with Sarnafil myself, But from the look of the pics you've posted, The joins/overlaps have come ''unstuck'' Surely it's common sense to lap the joints the other way?? So the water flows over the joints and not into the joints????

 

[freddiemercurystwin]

If its welded correctly it shouldn't matter.

 

[SurreyRoofingEstimator]

Hi,

I've not worked with Sarnafil myself, But from the look of the pics you've posted, The joins/overlaps have come ''unstuck'' Surely it's common sense to lap the joints the other way?? So the water flows over the joints and not into the joints????

No, it is correct, the flashing piece is welded to the front edge of the drip trim then welded to the field area thus creating the inward facing seam

 

[SurreyRoofingEstimator]

The weld failure can only really be endemic if either the hot air gun (machine) wasn't at a high enough temperature (which is unlikely) or the underside of membrane got wet, PVC absorbs the water and will not weld correctly if the case.

As far as I know you just need to run the seam tester down the weld with a little pressure and if it finds a failure it will go into the seam, another way (and more sure) would be a vacuum test over the seams.

 

[nute]

For what its worth although Sarna have a very good reputation within the industry their warranty is not very good.

They will seek to push the responsibility back onto the contractor every time and its darn hard to prove a defect in the materials which is the only time which they will act. If, as so often happens the roofer has gone out of business they are not interested.

Contrast this with felt manufacturers like Flag-Soprema and Nord or other single ply manufacturers like Cefil and you will see a difference if you ever have to rely on the warranty. These latter firms will step in if the contractor goes bust and in some cases will offer compensation for consequential loss.

As a specifier, although i have used Sarna in the past i would not do so again unless requested by the client.

 

[gwwxxx]

Having now seen Sarna on my roof I would not have it again.

The clean crisp solution in their marketing brochure is not what I have been supplied and the rubber has troughs and ridges running consistently where the edges of the foam insulation blocks occur - as if the tape they used on the joins has caused a failure in bond and the rubber sheet has since moved/expanded. It was fitted in February in borderline temperatures.

I asked the Sarna inspector about it and he said it was within tolerances - looks pretty awful at close range though.

Wish I had stumped up for a standing seam metal roof but followed the Architects advice instead.

 

[SurreyRoofingEstimator]

Unfortunately with any of the PVC membranes any details from below show themselves on the surface though fleece backed membraned can reduce this to some extent, the insulation joints are not (afaik) taped anyway.

The brochures always look nice, neat and smooth but in practice there will always be undulations from taped joints and such.

TBH you are looking closely at it as you have had an issue, in normal situations if all had gone well you would never notice such things