Exposed purlin ends - overhanging eaves - rot?

chaotic_j

Hi,

So the front, side and rear of the house has exposed purlins under overhanging eaves.

At the front, the purlins on the left hand side of the apex towards the top and middle of the roof have a lot of paint missing - I just assumed they had weathered and needed painting but they seem on their 'top' side to be down to the bare wood.

They are 8 x 4 and set at a 45 degree (ish) angle. They may have some kind of rot? looks like they have cracks and the higher up one seems to have a hole where it meets the soffit.

I've gone into the fully insulated attic space and jabbed the worst looking one with a screwdriver - it's solid. There is a cavity wall which is about 400mm thick which obviously I can't see into.

Doesn't seem to be anything amiss up there, some powdery spots on areas of timbers which come off if I wipe them with my finger, but no kind of bad smell. I've looked down the rafters as well - there's a piece of insulation board sitting between each of them.

Does anyone know what this could be, how it could have happened and how I can get it fixed please?

We have been here about 4 years, the purlins have been like this a while - not sure how long. The slate roof has vents dotted around it - there's a decent breeze up there. It's laid with impermeable felt also.

It looks like there may have been some difficulties in the past as some of the original planked soffits look to have gone a bit rotten - but nothing recent? some have been replaced with Plywood. We lost some slates etc. on the opposite side of the apex during storms earlier in the year but had this repaired.

Many thanks,
chaoticj

stuart45

You'll have to get up on on a tower scaff and do a bit of work on them.
Make sure the timber is dry  and then preservative, wood hardener, filler, paint. 
Probably got wet through missing slates at the verge.

chaotic_j

Thanks @stuart45 are you in the trade may I ask? you seem very knowledgeable.

The left hand side of the apex at the front and back of house had a wooden capping 'slate protector' - but none on the right hand side (I've had this added now).

Is it possible there could be damage to the slates under the front left hand side capping? maybe hard to tell without removing it? see picture. You would think this would keep them in place and undamaged though?



All houses I've seen of this style have that kind of capping, including the opposite end of the terrace which is the same house in a mirror image, so guessing it must be pretty standard (never noticed it was missing when we bought the place).

Could it be old wet rot in the purlins which was just painted over prior to sale? Is there any specific paint to use to repaint?

Thanks a lot!

stuart45

chaotic_j said:

Thanks @stuart45 are you in the trade may I ask? 

I'm a bricklayer by trade, although I have worked on a few roofs. The verge is a weak spot for slates getting blown off, especially when half slates are used instead of slate and a halves at the end. The cap helps protect them for any wind lift.
Probably be best to use a microporous paint, maybe Bedec MSP. Wet rot will only affect the areas of timber that are wet, so once dry should be OK.