Help needed; think i may have subsidence/ damp

DW123_2

Here's my contribution for what it's worth:-

1. You don't appear to have a problem anymore with the window, as you say you have cleared the mould. As stated before heat the room to dry it out and keep it well ventilated. Before you decorate it I would wait at least 3 months following the remedial work to ensure the walls & plaster have dried sufficiently and that mould has not returned. In all probability if the window was the only source and location of mould then the windows/gutters above them were probably to blame. Try keeping the guttering free of leaves particularly if you live next to a tree!! Water can come in through the roof line/eaves quite easily as it spills over each side of the gutter and tracks back into the house through capillary action. Unless the problem persists you don't need to get anyone out for this yet.
2. Have you checked the roof. Apart from missing slates if it is the original roof it may have the old fashioned "torching" where lime mortar was applied directly to the underside of the slate. The torching may have decayed to such an extent that it is no longer water resistant. You will know this because the loft will be very dusty and dirty, will smell fusty, damp and you may even see a hole!! BEST CASE Re-point WORST CASE Re-roof.
3. Old walls and old houses often have cracks. Stress cracks are a sign of possible structural shifting, extreme temperature changes, incorrect plaster mix, improper curing or leaks. Don't panic if your walls have small cracks, just keep an eye on them and determine if they are actively widening or stable. In most old houses, cracks mean that the keys of plaster that hold it securely to the lathe have broken (from one of the possible causes above). If the crack is old, and does not have any loose material, it probably is not anything to worry about. Hollow sounding plastered walls are a sign of blown plaster and generally would be attributable to age rather than settlement.
4. The join with the original part of the building is the weakest point and will no doubt crack. I would n't worry yet. Check externally that the join is still sound and if it is don't worry.

It seems to me your biggest problem is the damp which you appear to have cured. The plaster cracks appear more to do with age than structural movement. Blown plaster though needs to be remedied and it might be necessary to hack it all off and re-plaster the lot (or dot & dab and skim).
By the way is your extension a flat roof. 70's extensions were typically flat and flat roofs are !!!!!!s for leaks!!

cake21

As a quick aside, DW123, I think I possibly have a leaking flat roof (damp patches at edges of ceiling, I clear the guttering above it regularly)
Any advice as to what to do please?

slummymummyof3

Have you checked any lead flashing?

Vindiesel

Hi DW

thanks for all yuor inout, happy with what yuo have all told me, feel reassured. FYI the extn IS a flat roof, however (touch wood) I have a rubber roof now - 3rd roof since i bought the house, and it seems to be infallible. Would deffo reccomend, and not much dearer than traditional (waste-of-money) felted roofs.

PM if you live in Manc and want the contact details for co.

Cheers

DW123 wrote: »

Here's my contribution for what it's worth:-

1. You don't appear to have a problem anymore with the window, as you say you have cleared the mould. As stated before heat the room to dry it out and keep it well ventilated. Before you decorate it I would wait at least 3 months following the remedial work to ensure the walls & plaster have dried sufficiently and that mould has not returned. In all probability if the window was the only source and location of mould then the windows/gutters above them were probably to blame. Try keeping the guttering free of leaves particularly if you live next to a tree!! Water can come in through the roof line/eaves quite easily as it spills over each side of the gutter and tracks back into the house through capillary action. Unless the problem persists you don't need to get anyone out for this yet.
2. Have you checked the roof. Apart from missing slates if it is the original roof it may have the old fashioned "torching" where lime mortar was applied directly to the underside of the slate. The torching may have decayed to such an extent that it is no longer water resistant. You will know this because the loft will be very dusty and dirty, will smell fusty, damp and you may even see a hole!! BEST CASE Re-point WORST CASE Re-roof.
3. Old walls and old houses often have cracks. Stress cracks are a sign of possible structural shifting, extreme temperature changes, incorrect plaster mix, improper curing or leaks. Don't panic if your walls have small cracks, just keep an eye on them and determine if they are actively widening or stable. In most old houses, cracks mean that the keys of plaster that hold it securely to the lathe have broken (from one of the possible causes above). If the crack is old, and does not have any loose material, it probably is not anything to worry about. Hollow sounding plastered walls are a sign of blown plaster and generally would be attributable to age rather than settlement.
4. The join with the original part of the building is the weakest point and will no doubt crack. I would n't worry yet. Check externally that the join is still sound and if it is don't worry.

It seems to me your biggest problem is the damp which you appear to have cured. The plaster cracks appear more to do with age than structural movement. Blown plaster though needs to be remedied and it might be necessary to hack it all off and re-plaster the lot (or dot & dab and skim).
By the way is your extension a flat roof. 70's extensions were typically flat and flat roofs are !!!!!!s for leaks!!