Replacement fascia

[TheForge]

At the rear of our house we have a tiled roof over what was a sheltered 'porch' for the shodding of horses. Unfortunately, due to insufficient overlap of poorly laid tiles on the back wall of this water had been penetrating at the eaves and had rotted out the wall plate (leaving about 2 feet intact along a 5.5m wall) and several of the rafter feet.



We've replaced the wall plate, made some scarf repairs and added some sister rafters to the worst effected timbers.


However we now have a problem over the fascia. The fascia we removed was 6mm thick asbestos board and, as is apparent in the photos, there is virtually no overhang at the eaves. I'm intending to move the bottom row of tiles a few centimetres down to create a small overhang into the gutter but this will necessitate a very thin fascia (ie 6mm).

The only option I can see being viable would be a plywood board of some kind, but it must be relatively water and warp resistant. I was intending to use marine ply but have seen exterior ply advertised (and is cheaper). Can anyone explain the difference and/or recommend what would be the best option and where I might source it from?

 

[Flyfisher]

According to this, the difference between marine and external plywood is the quality of the veneers used in the construction. The actual glue is the same.
http://www.specialisedpanels.co.uk/marine-plywood.html

Given that fascia boards are fairly well protected underneath guttering, is primarily decorative rather than structural and will be protected with paint (I assume), then I reckon exterior grade ply would last many decades.

As for the fascia needing to be very thin, can you not arrange for the bottom row of tiles to overhang a bit more. You've already removed a few rows of tiles and if you re-batten then you could probably extend those tiles by about 1-2cm per row. It looks like you've removed 5-6 rows so even 1cm per tile would give you an additional 2 inches of overhang. Together with some eaves protection strip running into the actual guttering, this should be more than enough to allow a standard fascia board to be fitted. It would involve removing more tiles though and it's not clear from the photos how many.

Perhaps you could fix a trial piece of fascia, fix a guttering bracket to it and then work backwards from there to determine how much you would need to 'stretch' the tiles?

I replaced some fascia boards on an outbuilding that were very similar to those photos and fixed them directly to the roof plate, but I used pressure treated 25mm softwood. I reckon they'll see me out.

 

[a twig]

Perhaps you could fix a trial piece of fascia, fix a guttering bracket to it and then work backwards from there to determine how much you would need to 'stretch' the tiles?

I replaced some fascia boards on an outbuilding that were very similar to those photos and fixed them directly to the roof plate, but I used pressure treated 25mm softwood. I reckon they'll see me out.

Re-roofed our outbuilding the other weekend - replaced all rotten timber rafters, new breathable roofing membrane, and tiles back on. Did exactly the same with my fascia, pressure treated 5" x 1". Slapped a load of cupranol on so that the colour matched the rest of the building's timbers. Fascia screwed directly to plate, then fitted guttering - job's a good 'un. My tiles didn't overhang as much as I'd like, but I had some eave protectors left over from when my roof was re-done. Similar to the image below but with "fingers" to still allow air flow under the tiles.

With that fitted I now get a good run off into the gutter, and the timber underneath is protected.

I have two or three metres worth going spare if it's any good to you.

 

[88v8]

For the fascia I'd use oak feather-edge.

Eaves protector under the tiles is a good idea. Or, for a few pounds more, lead.
I presume you can't reduce the tile lap as that was the cause of the problem in the first place, so there's no easy way to get a better overhang. Especially with tiles such as yours where replacements need to be exact or they won't interlock.

Ivor

 

[billybuntus]

I would go with rise and fall brackets with cast iron guttering and epoxy black paint. Just done the same myself.

Use eaves protectors if you can fit them under if not just lift the bottom row of tiles and use visqueen sheet and overlap into your gutter.

Bugger painting facias.