Sealing felt roof on new shed?

[aww999]

Hi guys, I just put up a new shed in the garden, and I'm checking that I've done the roof correctly! It's an apex roof, about a 20 degree angle I guess. I was supplied with three rolls of felt, so I nailed a roll down each bottom edge of the roof which is secured under the eaves. The third roll then goes over the apex, overlapping each bottom roll by about six-eight inches. Should I seal this overlapping seam with something? Nothing was supplied with the shed, and no mention ofg it was made in the instructions, it just seems a bit odd to leave this seam unsealed. Water would have to track upwards, against the slope of the roof, for about eight inches in order to get in; is that sufficient to weatherproof it or should I be using bitumen or something to seal it up?

I saw the Daily Wail had a headline about a monsoon arriving tomorrow and it's got me worried!

[Red Firecracker]

Nah, you'll be fine. Once the sun gets on the felt it tends to make it a bit sticky underneath as well which always helps.

[Balmoral Green]

You could run a bead of silicon sealant along it for peace of mind, that would also act like glue and stop any high winds from lifting it at the overlap. The main problem for shed roof felts is lifting in winds, rather than leaks I reckon. Some wooden batons nailed down too would help.

As it happens, just orderd a 16x9 apex roofed workshop this morning, as soon as they have put it up, I will be making sure that the felt is well secured and sealed, as I don't expect it will be brilliant. Might put another layer on too, and will certainly baton it down.

[martinmac]

Should be fine as long as you have used the broad headed tacks. One about every six inches to stop the wind lifting it. Put many up and never had a problem.

[aww999]

martinmac said:

Should be fine as long as you have used the broad headed tacks. One about every six inches to stop the wind lifting it. Put many up and never had a problem.

That's exactly how I've done it, fingers crossed it will all hang together

[Hard-Drive]

Hmmm, technically speaking you really want to use some roofing felt sealant, black bituminous gunge that comes in a pain tin with the consistency of slightly runny chocolate spread and is a total messy arse of a job to do.

If it were me I'd probably do it if it's a brand new shed and you really want it to last, although as the others say it will probably be OK without.

[GreenV8S]

You are supposed to glue the layers together with bitumous adhesive stuff. I guess the main purpose is to stop the edges flapping about because I doubt much water would find its way up the gap.

[anonymous-user]

Balmoral Green said:

You could run a bead of silicon sealant along it for peace of mind, that would also act like glue and stop any high winds from lifting it at the overlap. The main problem for shed roof felts is lifting in winds, rather than leaks I reckon. Some wooden batons nailed down too would help.

That's what I tend to do, nail it all down and paint the sealant across the edges.

[GTIR]

You will be fine, thats how I did mine.

[Dogwatch]

GTIR said:

You will be fine, thats how I did mine.

+1

Probably need redoing in 3-5 years though. Wickes do quite a good 'how to' leaflet on felt roofing which explains what sort of lifespan you can expect from the different roofing felt materials available. Put a 2-layer self adhesive felt roof on a garden building, with an expected life of 20 years, but not cheap.