No insulation (and no space for it) = damp

ThisIsWeird

MouldyOldDough said:

The old structure is Lathe and Plaster !!

The roofer is going to quote me for removing the first 3 layers of tiles, putting in insulation and support trays and refitting the old tiles

He told me that the underlay was possibly breaking down - so he is also going to quote for a new roof - which the OH would prefer - but I believe is totally unnecessary - because whilst it is old (probably 50 years old) concrete tiles last for a lot longer than this...... ?

Lath and plaster is more messy, certainly, but is still vapour-permeable, and removing it is still the route I'd take - but then I'd be DIYing it (and climbing onto roofs ain't my idea of fun).

I still think it'll be the more effective way to insulate, too. With what you currently propose, the timber rafters will still be making contact with the L&P, just as it currently does.

But, if the outside bottoms rows of tiles DO need additional work in any case, then fair do's. Does it?

As with older boilers, you don't replace roofs until it's absolutely needed :-).

stuart45

It's possible that the felt has perished, especially at the eaves. 

FreeBear

ThisIsWeird said:

MouldyOldDough said:

The old structure is Lathe and Plaster !!

The roofer is going to quote me for removing the first 3 layers of tiles, putting in insulation and support trays and refitting the old tiles

He told me that the underlay was possibly breaking down - so he is also going to quote for a new roof - which the OH would prefer - but I believe is totally unnecessary - because whilst it is old (probably 50 years old) concrete tiles last for a lot longer than this...... ?

Lath and plaster is more messy, certainly, but is still vapour-permeable, and removing it is still the route I'd take - but then I'd be DIYing it (and climbing onto roofs ain't my idea of fun).

I still think it'll be the more effective way to insulate, too. With what you currently propose, the timber rafters will still be making contact with the L&P, just as it currently does.

If one uses rigid PIR/PUR insulation, it will sit on top of the nibs and leave an air gap. As a consequence, cold air will still circulate between the ceiling & insulation. Admittedly not as much, but still enough to lower the temperature.

Taking down lath & plaster ceilings can be fun (not). A very, very messy job that needs comprehensive use of decent dust sheets - https://forums.moneysavingexpert.com/discussion/6515965/plasterer-ruined-carpets - A small section of ceiling shouldn't produce as much mess...

ThisIsWeird

FreeBear said:

If one uses rigid PIR/PUR insulation, it will sit on top of the nibs and leave an air gap. As a consequence, cold air will still circulate between the ceiling & insulation. Admittedly not as much, but still enough to lower the temperature.

Taking down lath & plaster ceilings can be fun (not). A very, very messy job that needs comprehensive use of decent dust sheets - https://forums.moneysavingexpert.com/discussion/6515965/plasterer-ruined-carpets - A small section of ceiling shouldn't produce as much mess...

Yeah, a warning thread! Yours should be that bad, as it's on a slope!

Hmm, good point - the rigid insulation won't be making good contact with the wall board (L&P), so its insulating properties will be rendered largely ineffective, in my view. I don't know if this could be countered by, perhaps, by first laying on a thin layer of loft-type insulation, and then pressing the tight-fitting rigid against it, to squish it flat and fill any gaps?

But, again, I keep going back to - does your roof NEED to have this work done? If so, WHY? Is it leaking? Does the flow coming down that roof all end up in the gutter? If no and yes, then no work is needed to that roof. Best to save the money and put it towards a new roof recovering in a decade's time...

Your issue is - seemingly - one of lack of insulation. That's it. There is one good way to sort this. Well, two. You could just fit a sheet of insulated p'board over the existing wall slope, and that's that. But, (a), you'd have to be confident that cond was the cause, and you aren't just hiding a potential leak. And (b), you'd be limited in the thickness you could add, without interfering with your curtain rails and stuff.

Cutting away that slope would allow you to determine IF there's a leak, and then be able to add the best possible level of insulation.

MouldyOldDough

Have had a quote for  a new roof :
To strip entire roof covering
To remove tiles, felt & batten from site to a waste disposal facility
To supply and install roofshield underlay with all new tiling battens
To supply and install new Redland renown concrete tiles
To supply & install new concrete ridge & hip tiles complete with dry fixing systems
To supply and install underlay support trays
To supply & install rigid insulation to sloping ceiling areas
To supply and install firebreak to party wall with neighbour
To supply and install bonding gutter system with the neighbouring roof

£4900 + vat

scaffolding £1900 + vat

+ £375 to replace chimney flashing - if necessary.

That doesn't look too bad to me - I expected closer to £10k

Bearing in mind that there are three faces of roof to deal with 

Like this (this is NOT our property)

Ganga

Not £10k but with the VAT it will be nearly £8500 plus the possible flashing repair.

FreeBear

£8610 all in sounds reasonable with new tiles. Will that include Building Regs sign-off ?

MouldyOldDough

What is the best way to treat the mould - once the cause has been fixed ?

bear in mind that it is on the ceiling with "donkeys dinner" wallpaper on it............

MouldyOldDough

FreeBear said:

£8610 all in sounds reasonable with new tiles. Will that include Building Regs sign-off ?

Its all done - just waiting for the scaffolding to be removed

"Building control will not need to be notified of the works taking place & no fee will need to be paid, they are an NFRC Competent Roofer approved which means they can self-certify, it is also possible that these works could be randomly inspected by NFRC Competent Roofer themselves"

We had the flashing on both chimneys replaced - total cost (inc vat) £9092 which we find acceptible with a 10 year guarantee

ThisIsWeird

Sounds like a good outcome, MOD.

Let the damp patches dry out fully, then spray with mould killer such as 'Astonish'. That should bleach it nicely too. Hopefully it can then simply be overpainted with emulsion. If a stain comes through, then you'll need a stain block.

How did they insulate the ceiling?