Unknown Cause of Damp

[James_1999_Cheese]

Good afternoon folks,

In March 2025 we had two rooms replastered. Both of which are now showing random patches of damp.

We have recently had the chimney removed. The builders did a terrible job of putting the felt back where the chimney was. We had this remedied by the placement of eave support trays, so there are no leaks in the gutter and no water runs off the fascia boards now.

However, we are still getting damp patches which are exacerbated when it rains, not by size but by severity of damp. Would could be causing this?

The new plaster is gypsum - I’m not sure whether the old plaster is lime or not (photos attached for reference of old plaster). The damp in the bedroom follows the lines white “wings” in the old plaster above where the fire-place was (shown in image).

The house is pebble-dashed, build in 1935 and detached.

What could be causing this?

 

[JohnD]

Please stand back and take wider pics of the walls, floor to ceiling. And of the outside, roof to ground, showing gutters, downpipes, gullies and drains, and the foot of the wall, including the ground or paving, and nearby drains and manhole covers, and of the roof and loft, showing where the chimney was removed. Point out where the DPC is, relative to ground level or paving.

Is this wet on the ground floor?

Is it near kitchens or bathrooms?

Are the floors concrete?

How old is the house? (Edit, 1935)

Have you got a water meter?

What date was the plastering finished (Edit, March), and the roof leaks repaired? Have you had the windows open to dry it out?

Are the bricked-up fireplaces open at the top? If you have a large drill, it would be helpful to drill a hole just above the skirting. This will start to give a little ventilation to help dry out the cavity, but will also enable you to sniff it and insert a finger to see if it is damp, and to probe inside to see if the cavity is full of wet rubble ( builders like to throw rubble down chimneys and into fireplaces to save the effort of barrowing it out)

 

[James_1999_Cheese]

Good afternoon John D,

Attached image shows the roof on the affected side. The black mark is now inactive - was from the chimney which was buggered. The pebble-dash is not blown here.

This damp is on the first floor

Nowhere near any kitchens or bathrooms - bathroom is the other side of the house, as is the kitchen.

Floors are boarded

1935 - 90 this year

We have an amazon one with two prongs

 

[JohnD]

Thanks

I've updated my earlier post

The guttering looks modern, but surprisingly crooked. See if you can borrow some binoculars, or a long focus lens, and see if it could be spilling. Look during and after rain. The damp pattern seems consistent with a roof or gutter fault.

Have a look in the loft for damp or defects

I meant, a water meter that records how much water is coming from the mains into your taps, but I now think (unless you have a plumbing fault or overflows round a loft tank) that is unlikely to be the trouble.

 

[ree]

OP,
1. You have an existing external chimney breast that has had the chimney stack removed.
2. Internally, you show one blocked fireplace, and damp walls in two FF rooms. Can you post a pic of any second blocked off (?) fireplace?
3. Are there chimney breasts and fireplace openings below on the GF?
4. When were any of your chimney flues last swept?
5. Are the wall surfaces in the pics solid plaster or plasterboard?

6. Using a ladder & a selfie stick why not take pics looking down into the gutter & the patched-in roof repairs.
7. Take pics of any blown or cracked render.
8. Could you go into the loft & pic below the repairs?
9. Dont go drilling anything.