House built in 1974. There is a black woven membrane that has developed holes in places and rain has been coming into my loft. This is positioned underneath the wooden battens that the roof tiles rest on. Just had a couple of ridge tiles replaced as well as a section of membrane. The guy removed the tiles and fitted a thinner breathable membrane. I have inspected the loft and several of these battens that are visible where the membranes overlap are wet through and rotten. Should the membrane be on top of the wood? Is the rotten wood a result of damaged roof tiles? Some tiles look as though they are porous and are wet on the attic side. I understood the membrane to be a 2nd line of defence against the weather elements.The wet battens do not touch the roof joists as the black membrane is between the joists and the wood. Will I need a new roof? Please advice me. Thanks the photo shows the tiles sitting on the batten although it does not show it well the left side of batten has started to rot and is wet through View media item 86284
Wet rotten batons under Roof tiles
- Thread starter Dunmiedin
- Start date
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A photo would help, both inside and out.
It may be condensation or rain penetration or a combination of both.
Does the attic have ventilation?
It may be condensation or rain penetration or a combination of both.
Does the attic have ventilation?
There is ventilation. I understand how the black membrane is positioned in horizontal rows allowing the flow of any rainwater to progress downwards and out at the eaves somewhere. The places where I can see the wet battens the bottom edge of one row and the top edge of the next row have little or no overlap and almost meet where the wood is, so the rain from above soaks the wood instead of flowing downwards. The other rows overlap each other between the tile battens, so the condition of the wood cannot be seen without cutting the underfelt. Hope this makes sense. Thanks.
Several issues here - one is the tiler didn`t lap the felt enough when built , and probably didn`t allow enough lap on the tiles @ the same time . Main one is the water actually getting into the roof through perished felt . IF the tiles are not obsolete you could have them stripped and relaid with an extra course , new battens and membrane - can you post a pic. of the outside ?
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Type 1f felt non breathable!
What ventilation do you have up there?
I'm leaning to lack of ventilation here.
What ventilation do you have up there?
I'm leaning to lack of ventilation here.
There are grills at each end for ventilation. Another question I have please. Through the larger holes in the felt I can daylight. Does this indicate a problem with the roof tiles.?
Daylight can be seen in most lofts.
You need both high and low level ventilation, does the attic feel draughty when you open the hatch?.
You need both high and low level ventilation, does the attic feel draughty when you open the hatch?.
Very draughty. A lot comes in where the felt laps are and at the eaves. What photo is needed from outside? Can only see the top of roof on one side. Will do it now thanked ps what is f1 felt?
1f felt is tar based reinforced which is non breathable, and doesnt let the roofspace breath without additional means of ventilation.
Is your bathroom fitted with mechanical extraction?
Unblock and open up the laps in the felt....Any moisture created in your home ends up in the attic.
I still think its a moisture and venting control issue btw.
Is your bathroom fitted with mechanical extraction?
Unblock and open up the laps in the felt....Any moisture created in your home ends up in the attic.
I still think its a moisture and venting control issue btw.
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