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Thought roof leak was repaired, 2nd leak within 2 months. received conflicting advice from different roofers.

The 1st leak in Oct 11 repaired: Roof Loft, Repointing Rear Valley and damaged timber. Material used: Roofing flashing, silicon, sealant paint and some new tiles.
2nd leak in 14 Dec 11 in exactly same spot. Recall 1st builder, advice, new valley and relay all roof tiles to the staggered method using existing tiles. Says that he will guarantee the relay method he suggested as this was the way he's taught. Straight ( vertical ) tile alignment does not channel water away as efficiently, so when there's excess water, it'll seep underneath causing battens to rot. He showed me some damp patches and damp battens.
Another roofer did an emergency repair to stop my leak over christmas by using fibreglass resin to paint over the skylight area and other parts near the valley he feels will stop the leak. He claims this may last about 6mths - 1 year to allow me time to decide. This roofer says my tiles are in a pretty good nick and does not need re-roofing and the problem is the skylight area and the valley. So new skylight window and new zinc valley.
A 3rd roofer suggest new valley and new flashings. However, a complete new re-roofing to slate will solve all my problems.
The advice given are conflicting and I dont know who to believe or is giving the correct advice. Thank you for your help

4 Answers from MyBuilder Roofers

Best Answer

sounds like your skylight and valley is leaking, you do not say what type of tiles are on the roof and if their is any under felt in place
if the valley is leaking it is always best to replace the valley rather than try to repair.
if he re-pointed the valley , what did he re-point it with ?

without looking at the roof it is impossible to say what the best action is.

your best bet is pay a completly independent roofing company to do a report on the condition of your roof with the understanding you are paying for a report only and under no circumstances will any work that needs done be given to them , this will eleminate their need to tell you anything other than the true condition of your roof, and will then allow you to move in the direction that is best for you.

good luck and a happy new year


Answered 29th Dec 2011

First couple of roofers sound as though they have only done bodge repairs, and as for the staggered method, so best discount those two.
One has said tiles are ok, one has said they are not.
You need to find a recomended roofer to get up and have a look, its no use painting stuff every where and squirting silicone about.
It sounds that you need a new valley, this can be done in lead or preformed glass fibre, whichever the tiles will need to be stripped back either side of valley then relaid.
The flashings, front & back apron needs attention to the sky light.


Answered 29th Dec 2011

If the leak is around the skylight it could be an issue with flashing details around the unit. If it is a Velux window you may require a BDX felt collar detail with transverse drainage gutter, this allows any ingress of water externally to be easily deflected away from the Velux down onto the felt and into the gutter.

This detail is required under part L of the Building Regulations (Robust detail) I have encountered thousands of examples of this over the years as an ex Velux service technician.

If the skylight intersects with the roof valley you may require extra lead detail to deflect excess water flow away from the window.


Answered 12th Jan 2012

Don`t use any of the roofers you have mentioned.
Fibre glas paint waste of time its temporary
Zinc valleys expensive and if not fitted correctly even more expensive.
I take it the material used on your valley is lead there is a cheaper alternative to lead you can get fibre glass valley trays simple to install.
If you get a roofer ask for references and visit the references properties to look at the work thats been done and get other peoples comments.


Answered 12th Aug 2014

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