20 Jul 2019
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United Kingdom
Advice on damp needed please!

We live in a house built circa 1900 - salt deposits have started appearing on the chimney breasts in the attic bedrooms - had several roofers out. One said the pointing on the stack was fine, another said needs re pointing, another said render the stack to weather proof it. Damp specialist has been round - very decent guy, said no damp work was needed, it was the pointing that was the issue.

On a separate note, on the ground floor, we have bubbling and crumbling paint appearing just above the skirting boards on inside of the main exterior wall.

I’m naive to much building work and after a bit of googling, have read that rising damp is a myth and internal damp is often a result of modern plastering and pointing methods which no longer allow the house to breathe. Is this true? If so would checking out if the pointing needs fixing (cement taking out and lime mix putting in) and internal cosmetic work sort this?

As for the attic issue - which roofer do I believe?! I’m now also wondering if the stack has at some point had it’s lime mix mortar removed, hence the bricks cannot breathe and the salt deposits have appeared?

Please help! Don’t know which way to turn and don’t want to be ripped off by paying for an expensive damp proof course when the source of the problem may not be fixed!

Many thanks
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On a separate note, on the ground floor, we have bubbling and crumbling paint appearing just above the skirting boards on inside of the main exterior wall.

All round the house, or on one particular wall? For example that has the drains (full of water) or the incoming water pipe (full of water) beside it?

Is it a concrete floor or a wooden floor?

Can you see the DPC?

Post some pics, inside and out, of the wet wall, and especially any broken, cracked or sunken concrete of paving beside it, and of the airbricks.

BTW, chemical injections do not repair leaking pipes.
Thanks for your reply.
It’s one particular wall. We are a semi detached house and it’s the main unattached side.
See pics attached - really not sure what I’m looking at but there appears to be one air brick for the entire length of wall.
No idea what the floors are - the survey done last year says suspended timber and solid concrete. Don’t know what I’m looking for for the DPC? But old paperwork that came with the house says it was last done in 1992...


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Another pic


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Stand back and take some wider pics please.

The wall behind the bin is very wet.

As expected, that alley has drains from both houses, quite likely leaking.

It looks like it has been raining. Do the gutters over spill, and are there visible leaks from the downpipes?

I don't see gullies or original airbricks. Perhaps they have been buried.

Do you think the ground level in the alley has been raised since the houses were built? Look at similar houses nearby.

Look at the front and back of the house for original airbricks and original dpc, probably a thick mortar joint or a horizontal black line of slate. It would have been 9 inches above ground level when the house was built.
The 1992 paperwork probably relates to a chemical injection, probably useless, but indicates that damp has been a problem for at least 30 years.
For the chimney problem google Hygroscopic salts.
Removing the sand/cement pointing and going for a lime mix flush pointing and finished with the churn brush may help.
Struggling to find evidence of the dpc. Our downpipe doesn’t go into a drain but next doors does - wonder if this is an issue? The paving bricks on our side certainly look wetter. Cannot see any visible leaks from above. All other houses on the street have paved their alley so difficult to tell where original ground level was? But next door has a pebbled gulley...


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External ground level maybe too high.
Window by bins, measure from sill to ground outside and same to floor
Level inside , report back with the difference .
at first glance i'd suggest that:
1. the path has raised the ground level too high.
2. you maybe have solid stone walls with perishing pointing.
3. ask the roofers for photos of your chimney stack. where are the chimney breasts and stacks located?
4. get all your chimney flues swept.
5. are any flue fireplace openings blocked off?
6. presume you still have suspended floors?
7. only one 9"x3" air brick can be seen - plus a solid brick insert that probably replaced an original air brick?
8. DPC's were usually, and should be, located below any joist tail seats or air bricks.
9. how many air bricks, and where, can be seen around the house?
10. you will need to get the flooring and skirting and joist tails in the suspect walls examined for decay.

read the related threads below
Many thanks to you all. Got someone coming on Tuesday to take a look so will write your comments above down as questions to ask
someone coming

I hope it is not someone who sells chemical injection treatment.

An experienced local builder is likely to have seen lots of houses like yours.

Very alarmed if your rainwater downpipe does not go into a drain.

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