support for roofing felt at eaves

[wobbly2]

Hi All,

I'm trying to help a friend with a problem with some garage roof repairs. The garage has sectional precast concrete walls with a steel angle iron trussed roof covered with Marley(?) Mendip(?) concrete tiles. The trusses are topped with 64x32mm timber that does not extend beyond the outer edges of the walls.

There appears to be a problem(?) with the installation of the roofing felt as it goes over the fascia board.

The felt, which seems to be of thin poor quality, has been dressed down the trusses to a position approximately 50mm below the top of the fascia and nailed into place at each end with the cement board supporting the edge tile mortar bedding fixed on top. The felt then rises to go up over the fascia creating a trough of about 50mm deep behind the fascia. The felt/tough is cut flush with the outer face of the end walls (which at that point is timber) meaning any water it carries can only escape by running down the end walls and possibly back under the felt into the garage, which does not seem correct.

In addition, the edge of the felt that lays into the gutter has rotted and, as a temporary measure, 18" wide DPC has been installed under the felt and up over the fascia to lay in the gutter.

The roof does not have a soffit as the fascia is fixed directly to the timber wall plate and the ends of the timbers that top the steel trusses. The timber wall plate does not support the roof and appears to provide purely lower support for the fascia.

The spacing between the trusses is not even at 550mm, 700mm, 1000mm, 920mm 540mm, 620mm & 670mm centre to centre and the felt between the 900mm and 1000m spacing definitely sags quite a bit. I had thought to install tile fillets (if that’s the right term) and then possibly lay 9mm x 300mm WBP ply across them to support the felt. Alternatively, a friend suggested that there is a semi-rigid plastic product available that fits over the top of the fascia extending at an angle part way up the trusses providing support the lower edge of the felt, the correct angle for drainage into the gutter and negates the need for tile fillets or further support but neither he nor I know any more.

Although I’ve said the trough behind the fascia does not seem to be correct it may well be acceptable for a garage, however, the garage is not used to store a car but more as an extension to the house so any advice would be much appreciated.

 

[noseall]

Why is there a problem with water ingress if the roof is tiled?

Why is the rain-water not flowing down the tiles and into the gutter?

How are the roofing battens (laths) supported over such large spans?

Why on earth is someone living beneath such a bodge?

Tell them to build a proper roof, with a soffit and fascia and correctly spaced rafters.

What is the pitch of the roof?

 

[wobbly2]

Why is there a problem with water ingress if the roof is tiled?

Why is the rain-water not flowing down the tiles and into the gutter?

How are the roofing battens (laths) supported over such large spans?

Why on earth is someone living beneath such a bodge?

Tell them to build a proper roof, with a soffit and fascia and correctly spaced rafters.

What is the pitch of the roof?

Thanks for your reply noseall

There does not appear to be much if any water ingress at the moment although there is at least one tile cracked along its top ridge so ingress is likely I guess.

The water is flowing down the tiles into the gutter.

The battens are nominal 35 x 25 treated timber nailed into the 65 x 35 timbers bolted to the top of the steel trusses.

My description of the use of the garage was obviously mis-leading. No one is actually living in the garage but it is being used to store things other than a car.

Due to cost, telling them to build a proper roof etc is not really a realistic option.

The trusses sit directly on top of the 610mm wide concrete wall panels and are bolted in place through precast holes in the edge of the panels. The odd spacings of 1000mm and 900mm are due to the inclusion of a side door and 2 side windows.

The roof pitch is approx 20 degrees.

There is another issue that I forgot to include in my OP and that is the mortar bedding for the edge and ridge tiles appears to have very little cement in it and is very crumbly. Bearing in mind the garage is only about 10 years both the mortar in both areas is showing signs of excessive weathering and crumbling, which presumably will add to the likelihood of water ingress.

I've taken some photos if it helps?

 

[noseall]

At 20 degrees the tiles you mentioned are not suitable for a pitch that shallow.

It sounds to me as though someone has added a tiled roof to a concrete sectional garage hoping that it will be ok without much modification or an awful lot of thought.

I'd walk away if they are not prepared to spend any money. Bodging a bodge is not going to make things any better and you may land yourself with the responsibility.

 

[noseall]

It sounds to me as though someone has added a tiled roof to a concrete sectional garage hoping that it will be ok without much modification or an awful lot of thought.

Reminds me of one of Freddies favourite sayings...."lipstick on a pig".

 

[wobbly2]

It sounds to me as though someone has added a tiled roof to a concrete sectional garage hoping that it will be ok without much modification or an awful lot of thought.

The garage was replace by her insurance company using a professional company after a tree fell through the old one about 10 years ago. The roof choice was her's but no one advised her the choice was a pig or a sows ear come to that or the roofer(?) appears to have been a nob.

I'd walk away if they are not prepared to spend any money. Bodging a bodge is not going to make things any better and you may land yourself with the responsibility.

Abandoning my friend is not really on, it's not her fault she was sold a pup and having started I do feel obliged to do something that improves the situation. There is money available just not enough the replace the whole roof.

The steel trusses are an integral part of holding the wall sections up, so replacing them, with say timber to form a traditional style roof, and then re bracing the structure would be way to expensive and most likely not cost effective.

I take your point about the roof angle being low. We could treat it as a pitched flat roof and double felt it then I understand the the pitch isn't so much of an issue, however, that doesn't solve the issue of the felt being dressed down behind the fascia to form a trough.

There must be some solution that would improve things. Wouldn't installing eaves protectors or fixing a rigid boarding (e.g. cement board) between the lower end of the trusses and the top of the fascia and putting in some noggins to support the protector or boards across the bigger truss spacings, not do the job?