replacing pitched felt roof with tiles

[hummer]

I am planning on replacing single pitched 15 degree 3 layer bituminous felt roof on 2" Stramit (approx 40 years old) with reconstituted slate tiles. I have been told i will need building regs for this and assume they will want to check roof loading. I have searched all over the place but can not find any info on weight of Stramit or roofing felt. Can anyone help?

 

[masona]

I'm assuming this is an extension added on if so, pop down to your local BCO and they should have the drawing details of your roof layout. Do you know the size of the joists plus centre etc

 

[hummer]

It was the original roof for the main house and single storey lounge that juts out. Both are single pitch at 15 degrees. It is an early 60s individual architect designed place, with dodgy felt roofs
Upstairs is timber frame, downstairs brick and block.
The original house drawing quotes 3 layer bituminous felt on 2" Stramit.
Rafters 8"x2" on 16" centres.
Upstairs walls 4"x2" on 16" centres.
Ceiling joists 4"x2" on 16" centres.
Various cross pieces are fitted.
I was just assuming weight of 3 ply felt and 2" Stramit would be less than battens and tiles (Lafarge cambrian) but this might not be the case.

 

[Static]

Depending on the thickness of the strawboard. On the up side the rafters are a good size and assuming your roof isnt more than about 3.5m in span you shouldnt have too much problem.

 

[masona]

Also make sure the roof tiles is suitable for 15 degree.

 

[Nige F]

Y`know that would look nice with a sheet metal roof But cost£££...makes me wonder if it was originaly designed as such...and the builder got cold feet on the cost?Copper would be beautifully patinated by now.

 

[masona]

Y`know that would look nice with a sheet metal roof But cost£££

I've used the roof tiles effect metal sheetings and the costs is not much difference.

 

[hummer]

Roof now on, scaffolding coming down on Tuesday.
I had a few leaks before the tiling was finished as the rain wasn't running off the felt well due to the low pitch, nothing 18 buckets, pot/pans, etc couldn't handle!
Even though the replacement roof was lighter than the stramit and felt, the building inspector insisted on triangulating the main roof joists. This took a couple of days and has rendered a small loft space into a useless one.
It looks a nice roof from the scaffolding, shame you can't see it from the road due to the low pitch!
Thanks for the advice/comments.