Is there anything better than black exterior mastic (frame sealer) to repair a foot long crack in a bitumen felt roof? The crack is near the edge where there is a lip to control direction of water flow.
Some has used what is now hard grey stuff to repair some previous blemishes in the tiles. It is subsequently cracked.
You can get roof sealant cartridges which I think are bitumen based and should retain some flexibility.
Thank you. Screwfix sell Mapei Backfill Bitumen sealant cartridges. They are twice the price of their other roof sealant products. I wonder if they are any better.
Bitumen is cheap stuff. General approach to roof cracks: Fill crack with sand & bitumen Apply bitumen Apply cloth. Anything can do but synthetic fibres last better. Apply bitumen Apply sand.
NT
With a long crack, it might be worth applying a felt patch, bedded on mastic from a tin (slightly cheaper than cartridges).
Aquapol with its reinforcing scrim? Wonderful stuff.
Flash band on top of bitumous mastic. Use the flashband primer. Best done in warm weather. Unfortunately.
I have used this on my felt shed roof with good results. I believe it is bitumen with fiber particles to strengthen it.
+1 Aluminium strip with about 2mm bitumen on one side. I have found it very effective when it is used with the appropriate primer. It can easily be moulded. I used it once to seal a circular downpipe going through a flat garage roof. Very effective
Malcolm
I repair my flat metal kitchen extension roof with a length off a roll of grey foil with bitumen layer obtained from a roofing merchant. Heat from a blowtorch melts it onto the metal.
Over the split in the metal caused by slates falling off the main roof onto it, corner first.
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