Rotten from possible leak on purlin

[Hkphooey]

Hi guy's
just found a bout 3 foot section of roof purlin in my loft which we converted about 15 years ago Victorian terrace.
When we converted it we rand another purlin along side the original just because, but the wet rot has got to both.
Its right under the velux but cannot see any obvious signs of window leaks BUT condensation is quite bad up there we run a dehumidifier and it been fine but noticed the damp and once i started chipping plaster away found the rot.
Can use a steel to it if rots not too far in , ive only taken it back and looks like just a section about 3 foot of the timbers.

 

[Hkphooey]

https://imgur.com/a/wVV92M9

 

[Hkphooey]

Not as bad as it looks at that's plaster board taken off and was dark up there, I'm wondering if I use metal plates to fix will it be too much weight to add to it?
Also want minimum disruption as its a bedroom, obviously I'll do what's needed and I'm thinking condensation has been running in from back as plaster on room side was OK,.

 

[Hkphooey]

Before plaster went up
https://imgur.com/a/nA91b5u

 

[martin hill]

Hi There

Couple of questions as that looks like polystyrene sheets.

Did you do the conversion yourself ?
How much insulation and what kind is present ?
Have you a cold loft space behind the dwarf wall ?
Was a vapour control barrier installed ?

In the process of having my done now and it's a mind field if a D.I.Y job as it can go very wrong due to thermal bridging/condensation etc. I'd check the bottom flashing on the window outside first and post a couple of pictures for the pro's to see. If maybe flashing damaged on the window thats letting the water drip down onto the purlin. I know you say its a bedroom and you want minimum disruption but i'd be doing a couple of test holes in other places if not a leaky flashing to see if you have an issue anywhere else that hasn't surfaced yet. Better to get fixed in one big job than several small ones.

 

[Hkphooey]

Hi There

Couple of questions as that looks like polystyrene sheets.

Did you do the conversion yourself ?
How much insulation and what kind is present ?
Have you a cold loft space behind the dwarf wall ?
Was a vapour control barrier installed ?

In the process of having my done now and it's a mind field if a D.I.Y job as it can go very wrong due to thermal bridging/condensation etc. I'd check the bottom flashing on the window outside first and post a couple of pictures for the pro's to see. If maybe flashing damaged on the window thats letting the water drip down onto the purlin. I know you say its a bedroom and you want minimum disruption but i'd be doing a couple of test holes in other places if not a leaky flashing to see if you have an issue anywhere else that hasn't surfaced yet. Better to get fixed in one big job than several small ones.

Many thanks that all makes sense, yes got check later today I can see at back behind the storage which is airey as nothing in that part seems isolated qhich is a bit weird, and nothing was evident on the plaster side was only when I went into the storage space other side I noticed bit of damp as all in fine there.
Was a DIY job but was advised by people in the know but was nearly 20 years and and all has been fine

 

[Hkphooey]

Dreading uncovering worse if I'm honest

 

[^woody^]

That's a roof leak, and that could be contributing to any condensation.

If the timber is not soft then it will revert to normal once you sort the leak out. Leave it, and wet rot can become dry rot and then you are in trouble.

 

[Hkphooey]

That's a roof leak, and that could be contributing to any condensation.

If the timber is not soft then it will revert to normal once you sort the leak out. Leave it, and wet rot can become dry rot and then you are in trouble.

Cheers bud... Yeah crazy no idea where from though seriously no sign on it anywhere.
Yup wood's dried out now and apart from some flake off it's dried solid
I'm sure it's from velux but just can't work it out. Leaving it open and can see as it's only a certain patch

 

[datarebal]

external pictures around sky light....

 

[Hkphooey]

external pictures around sky light....

Well it's flashing isn't great they leaded as well as used the kit maybe cut opening too large but like I say been nearly twenty years since we did it.
Will post pictures