NEW ROOF SHOWING DAMP ON FELT

[par1sons]

Hi again,

Yep had some heavy rain over the past few days but yesterday was heavy and long. Parts of my breathable felt were damp along with the roofing timber. This damp appears a few feet from the gutter but yesterday i found small damp marks about a 1.5 meters up the roof from the gutter so i have ruled out blow back from the wind.

The angel of my roof is 17º but i have a horrible feeling the headlap isnt the min of 100mm for my particular tile (double roman). I reckon it could be this headlap which is the problem. However if the headlap is fine what else could it be?

Secondly why do we have to use breathable felt, what was wrong with the old stuff??

Andy

 

[joe-90]

Secondly why do we have to use breathable felt, what was wrong with the old stuff??

Andy

It encourages condensation.

 

[par1sons]

yeah i suppose but given my house has the old stuff and it doesnt suffer with any condensation problems it just seem strange. Suppose it all depends on the ventilation of your house.

Given my new roof is now leaking, i can see why the old stuff would be much better, it least the water would run down into the gutter rather than just drip straight down on to the floor.

 

[SurreyRoofingEstimator]

If you've got water dripping on the inside you've either got condensation issues or there is something wrong with the felting.

 

[RedHerring2]

Just been informed by the BCO today that you can't really mix the old felt style with breathable membrane.
I don't know if this is the same in your case but, accrding to BCO, part of roof lined with non-breathable felt should be separated off and insulated from new part of roof with breathable membrane.
BCO reckons the migration of vapour from non-breathable part of roof to breathable part is too much for it to cope with.

I've managed to avoid it by a) treating ventilation in new breathable part the same as if it was non-breathable felt and b) in the near future, which was planned anyway, stripping the one side of roof that abutts new roof and replacing old felt with new membrane.

 

[^woody^]

..... you've either got condensation issues or there is something wrong with the felting.

I'd go further an say the OP has got something wrong with the tiling, as the membrane should not be getting too wet in the first place.

Also, condensation would not normally be occurring with the weather as it is of late

And if this is related to the OP's other post about the roofer overcharging on the final invoice, then it needs to be sorted out

 

[noseall]

Just been informed by the BCO today that you can't really mix the old felt style with breathable membrane.

Dave Small....???

 

[par1sons]

..... you've either got condensation issues or there is something wrong with the felting.

I'd go further an say the OP has got something wrong with the tiling, as the membrane should not be getting too wet in the first place.

Also, condensation would not normally be occurring with the weather as it is of late

And if this is related to the OP's other post about the roofer overcharging on the final invoice, then it needs to be sorted out

woody your right mate. Had nothing but problems since i got these guys to build this roof, thing is i can do this kind of stuff myself but just have not got the time due to my job etc so i thought pay the money out, come home and job done!!! how wrong was i.

I measured the headlap tonight and its 90mm rather than the min standard for double roman which is 100mm min. Im gonna have fun and games now and of course hes going to get cheesed off because i will be questioning his work. There are one or two other issues relating to the roof and thats the eaves trays. The roofer reckons there are ok to butt up against each other yet it clearly needs 100mm overlap but would he have it would he hell. He then bodged the eaves trays but i simply didnt have the energy to complain...im gonna sort it properly myself

andy

 

[RedHerring2]

Just been informed by the BCO today that you can't really mix the old felt style with breathable membrane.

Dave Small....???

No JE. Is that his colleague?

 

[par1sons]

sorted my eaves trays out saturday and whilst i had a load of tiles off my canopy and garage roof the bloody builder turned up...he was not happy with me. I explained i wasnt happy with the installation of the trays and i felt i had do it correctly myself.

My roof is still leaking and was really bad this weekend with water dripping through the felt all over the place. The roofer said hes goona put some tile sealer under the tiles to stop the water getting under the tiles, is practical?? or should he be putting a few extra rows of tiles in??

The angel of my roof is 17º right on the limit and 6.5m long by 2.5m wide. His headlap is only 90mm which is under spec. I reckon the roofer needs to headlap my tiles by half a tile (150mm) to be safe given the angel of my roof. Thoughts??

AND why is it, the felt which is now available can leak. i thought felt was used as aid to transport any leaking water down into the gutter? Surely breathable felt services no purpose, why not have no felt if its going to leak water??

I've had a bad weekend, sorry guys

Andy

 

[^woody^]

The angel of my roof ...

You will certainly need one to look after your roof by the sound of it

Breather membrane is less tolerant of stretches and tears and does not self-seal at the nails like bitumen felt does. So it needs more care in fitting

You need to sort out the underlying cause of why rain is getting under the tiles, and not let the roofer bodge it with any sealant which will only last a few years at best

 

[par1sons]

The angel of my roof ...

Woody well pointed out mate, lol. Its the stress of this roof, im wishing an angel will appear wave her lovely magic wand and all will be fixed.

Im an easy kind of guy whos buttons are being pushed to breaking point, he may cop some verbal very shortly

Cheers woody

Andy

 

[SurreyRoofingEstimator]

s

The angel of my roof is 17º right on the limit and 6.5m long by 2.5m wide. His headlap is only 90mm which is under spec. I reckon the roofer needs to headlap my tiles by half a tile (150mm) to be safe given the angel of my roof. Thoughts??


Andy

125mm will be your maximum headlap, any more and the tiles will ride up in each other

 

[jenny84xx]

We had a similar problem in our porch.

 

[par1sons]

s

The angel of my roof is 17º right on the limit and 6.5m long by 2.5m wide. His headlap is only 90mm which is under spec. I reckon the roofer needs to headlap my tiles by half a tile (150mm) to be safe given the angel of my roof. Thoughts??


Andy

125mm will be your maximum headlap, any more and the tiles will ride up in each other

Nice one thanks for that.