No insulation (and no space for it) = damp

Emmia

MouldyOldDough said:

in_my_wellies said:

My house has this sort of roof. The blurb called it 'galleried ceilings', it's 1908.
When we moved in in 1883 the ceilings were black with mould in 4 of the bedrooms, mostly behind 1950's style hardboard built-in wardrobes. 
We striped out the wardrobes and installed an airbrick in each bedroom and the problem has never returned even in the rooms which are largely unheated. I thought the airbricks would be drafty but TBH I don't even notice them now

We still have airbricks in each room but they make no difference
We also use an electrical dehumidifier every time that we have a shower

Do you not have a proper humidstat extractor fan in the bathroom? Irrespective of the cause of the damp issue in the bedroom I'd be trying to sort out sources of internal moisture like showers, baths etc. 

MouldyOldDough

Emmia said:

MouldyOldDough said:

in_my_wellies said:

My house has this sort of roof. The blurb called it 'galleried ceilings', it's 1908.
When we moved in in 1883 the ceilings were black with mould in 4 of the bedrooms, mostly behind 1950's style hardboard built-in wardrobes. 
We striped out the wardrobes and installed an airbrick in each bedroom and the problem has never returned even in the rooms which are largely unheated. I thought the airbricks would be drafty but TBH I don't even notice them now

We still have airbricks in each room but they make no difference
We also use an electrical dehumidifier every time that we have a shower

Do you not have a proper humidstat extractor fan in the bathroom? Irrespective of the cause of the damp issue in the bedroom I'd be trying to sort out sources of internal moisture like showers, baths etc. 

No - not in the bathroom

We have a wall vent (and in the affected bedroom as well).

jennifernil

ThisIsWeird said:

I guess line the inside with insulated plasterboard? It'll also be more effective than insulation added to the other side.

Mitre the board edges to fit nicely against the wall and upper ceiling. Jobbie should be jobbed?

Photo of the inside, MOD?

I would second this.   We have just had internal wall insulation installed in our Guide Hall, were supposed to get Kingspan Kooltherm 82.5mm, but it was unobtainable, so have 70mm of Kingspan with separate 12.5mm plasterboard.   The difference in the building is absolutely amazing!

70mm gives us a u value of 0.3 if I remember correctly.  Now getting the floor done too 

stuart45

FreeBear said:

stuart45 said:

ThisIsWeird said:
Water can follow tortuous paths, but rarely defy gravity

Apart from rising damp. Sorry, forgot it's a myth that was invented in1962 according to Peter Ward.

Rising damp does exist, but not to the extent that the PCA would have you believe. I know of only one case - The wall was built out of some very soft reds with lime mortar, and sitting in saturated soil with water pooling at the base.

If you know of one, then it's fair to assume there's more. The problem with rising damp is that it can be quite difficult to diagnose. 
Salford Uni managed to get a large amount of funding to investigate true rising damp about 10 years ago, and the results of about 4 years work produced a 400 odd page document that's findings were that rising damp does exist, especially in old properties with no DPC.
A friend of mine sent me a copy some years ago and it does seem quite a comprehensive study. A bit different to Jeff Howell's building of brick piers and standing them in trays of water in the college basement for a few months.

Emmia

MouldyOldDough said:

Emmia said:

MouldyOldDough said:

in_my_wellies said:

My house has this sort of roof. The blurb called it 'galleried ceilings', it's 1908.
When we moved in in 1883 the ceilings were black with mould in 4 of the bedrooms, mostly behind 1950's style hardboard built-in wardrobes. 
We striped out the wardrobes and installed an airbrick in each bedroom and the problem has never returned even in the rooms which are largely unheated. I thought the airbricks would be drafty but TBH I don't even notice them now

We still have airbricks in each room but they make no difference
We also use an electrical dehumidifier every time that we have a shower

Do you not have a proper humidstat extractor fan in the bathroom? Irrespective of the cause of the damp issue in the bedroom I'd be trying to sort out sources of internal moisture like showers, baths etc. 

No - not in the bathroom

I'd look to get that sorted.

MouldyOldDough

Apparently - its a classic case of "cold spotting" - ie) condensation

but how did water vapour get through the ceiling board to the timbers in the first place ?

lack of insulation etc

Remedy

The first 3 or 4 courses of tiles will need to be removed to allow for a rigid insulation to be installed in-between the rafters 

Tiles are then re-instated with new breathable underlay, tiling battens & underlay support trays

 

Roughly how much should this cost ?

MouldyOldDough

FreeBear said:

See image below - There should be a strip of plastic or felt under the tiles that cover the top of the facia boards. This would stop any water getting in behind the facia and soaking the timbers.

We don't appear to have any Over fascia vents and definitely no Eaves protector (at least none added when we had the plastics replaced ..

the tops of the fascia boards are just screwed straight on to the ends of the joists

with the gutters on to the fascia boards

ThisIsWeird

MouldyOldDough said:

Apparently - its a classic case of "cold spotting" - ie) condensation

but how did water vapour get through the ceiling board to the timbers in the first place ?

lack of insulation etc

Remedy

The first 3 or 4 courses of tiles will need to be removed to allow for a rigid insulation to be installed in-between the rafters 

Tiles are then re-instated with new breathable underlay, tiling battens & underlay support trays

 

Roughly how much should this cost ?

So, Stuart was right - damn.

Er, I mean, that's great news, 'cos it's much easier to fix.

And the way to fix this is from the inside - more effective, and far cheaper.

How does the cond get through the p'board? 'Cos it's permeable to water vapour. Plasterboard - like most 'wall' materials - 'breathes', and water vapour can, and does, pass through.

I'd personally only entertain the external repair if support trays are required, for example. But, if your existing outer roof covering is working fine, then the sensible approach is to cut away your 'slope', tightly fit as much rigid as you can between the rafters, and then overboard with 1-2" insulated p'board. The result will be called a 'cure'.

MouldyOldDough

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...... ?

MouldyOldDough

GDB2222 said:

Sometimes, plastic fascias are added on top of the wooden fascias. Then the gutter is screwed back, but the felt that’s supposed to overlap into the gutter is now too short.

Ours were replaced - not just capped !

the original were fully removed

BUT I see no eaves protectors at all