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Damp Proofing

Do I have damp or a leak or condensation?

Anonymous user 03/03/2024 - 3.36 PM

My property is a 3 bed semi detached built 50s/60s, pebble dashed with bricks behind it, no insulation in walls, ground has 3foot space which is insulated. Side of property wall is wet on upstairs bedroom, the downstairs room below in parts has dark marks these marks are not like mould when there is condensation but more so black marks like when rubber scrapes on white surface, the floorboards that laminate is on top of on this part closest to the wall are wet. The outside of the downstairs has a pebble dashed chimney breast shape sticking out in garden runs up to the bedroom, the bedroom part of chimney breast is indoors and is wet. The entire roof has been replaced about 9yrs ago, since this issue we have gone down root of condensation so replaced windows, opened air vents, the chimney has been capped off as not in use and roofer had advised could be the issue. From outside when rains the chimney breast pebble dashed wall is darker than the rest of the walls. Does this mean there is a crack? Main worries if turn the bedroom into a child nursery room and them breathing in the air of that room would it cause them harm? Any way to determine the root cause would be appreciated.

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4 Answers

Damp and Mould Solutions

Rating: 5 out of 5

Willesden, London

Are the affected walls external? Black marks points towards condensation. You require the correct balance of heating, insulation and ventilation. This winter has been cold with no wind factor, which has resulted in more people than usual reporting black marks and condensation. Turn up the heating by 1 or 2 degrees and keep it constant as possible, with no sudden drops. Cross ventilate where possible 3 times a day for 20 minutes. Open the window only an inch, when the heating is on and this should help. If, it does not work you need a mechanical solution. Check the chimney has been capped off correctly

Answered18 January 2021

Damp Investigations

Rating: 5 out of 5

Southall

The advice you have been given by the roofer has made it worse , actually, if the chimney is not ventilated . The chimney flue must be ventilated or it will become damp from hygroscopic salts in the flue called ammonia sulphate. And yes, it’s worse after rain but has nothing to do with rain . Google the condition now you know what it is so you can rectify it . Black marks that wash off are bad for children , if it doesn’t wash off , it’s ammonia sulphate, harmless .

Answered18 January 2021

ADR Property Maintenance

Rating: 5 out of 5

Boston

its really impossible to diagnoise what is happening without actually viewing the problem, the age of the house , condition of the brickwork condition of the roof, espically at this time of the year when the weather is especially cold, capping the chimney was not the wrong advice if it was vented but again it depends what was used to cap the chimney., is the building solid brick does it have a cavity, does it have wall insulation there are two many diffrent things that can cause dampness, without looking its impossible to diagnoise, firstly just because the roof is new doesnt mean its not causing an issue, there are lots of cheaper under felts on the market bs standard that are not fit for purpose & only have a short life span before degrading. is the insulation fitted correctly, is there enough air flow in the loft although there is a cavity with no insulation in it doesnt mean there is no blockage allowing bridging., condensation can not be ruled out as a cause but as i satd without viewing the issue its impossible to make a propert dignoises

Answered19 January 2021

Anonymous user

Although I agree to some of the measures I feel that the chimney flue could be the culprit it states that the chimney is not in use and capped off however does this flue have ventilation otherwise the flue will sweat and become damp and burnt coal/coke residue could leech through to the surface and contaminate the plaster surface and this could be the dark patches/stains now present.

Answered16 February 2021