Chimney Breast Removed, Now Mouldy Skirting

[simojo]

Hey all, we recently renovated our first house (built 1930s) with the help of a local builder. As part of this we removed the chimney breast (unfortunately not properly capped when we purchased the property) from the ground up and that area was dot and dab replastered and MDF skirting installed. 3 months on despite using a dehumidifier when needed to keep moisture levels down, there is green and white mould that keeps coming under the skirting. Is this from the years of the chimney being not properly capped, damp coming out from the plastering (was very very humid in the house when this was happening) or anything else? Currently thinking of taking the skirting off and trying to mould treat, try and dry it out and then replace with solid wood skirting. Any thoughts as to whether this is best course of action?

 

[JohnD]

Photos will help. The entire wall, up to the ceiling, and outside, up to the roof, and down to the ground, including all drains, pipes and downpipes, and showing the ground level relative to the DPC (use chalk to highlight it if not clear)

What is the floor made of? Can you look under it?

Was the old hearth dug out and filled in? Is there any DPM in it?

 

[simojo]

Photos will help. The entire wall, up to the ceiling, and outside, up to the roof.

What is the floor made of? Can you look under it?

Was the old hearth dug out and filled in? Is there any DPM in it?

Thanks for your reply. Unfortunately the photos would just show a freshly refurbished wall as I have been trying to keep on top of the mould. It is only coming from underneath the skirting between it and the laminate flooring.

It is a solid concrete floor with the area where the old hearth was levelled with self levelling compound.

I think there was DPM in the flooring but not sure if under the self levelled area (less than 1 metre square.

 

[blup]

Check tne ground level outside, sometimes the dpc is bridged which would transfer damp to back of skirting.

Blup

 

[JohnD]

Is the concrete floor original or does it replace an earlier wooden floor

The photos will show size and shape of damp patch. The outside photos will show potential sources of damp.

The old hearth will not have had a DPM as they relied on the fire to dry it and the chimney to ventilate it.. You might need to dig it out

 

[simojo]

Is the concrete floor original or does it replace an earlier wooden floor

The photos will show size and shape of damp patch

It is the original concrete floor as far as aware, no earlier wooden floor. There is no damp patch, just green fluffy mould that appears from under the skirting. Not a mark on the actual wall itself.

Check tne ground level outside, sometimes the dpc is bridged which would transfer damp to back of skirting.

Blup

Where the mould is, is on the adjoining wall. There were some issues on the front wall confirmed by a damp person on purchase inspection but this has been solved with lowering the ground level 30 cm, adding gravel drainage channel and then using DPM on inside wall.

 

[JohnD]

Looking forward to seeing the photos.

 

[simojo]

Looking forward to seeing the photos.

 

[simojo]

View attachment 313717

As mentioned, unfortunately no damp visible, the coins are to add a little extra ventilation while running dehumidifier, it is this gap that the mould comes out off in the middle of the wall where the chimney was removed

 

[^woody^]

A chimney breast does not have a DPC, and any damp typically migrates through the brickwork and evaporates away before you notice or mould has chance to grow.

When a breast is removed, its important to deal with the hearth, concrete floor junction, and the sections of wall immediately either side of the beast, or take other precautions to prevent damp coming up where the old beast was.

 

[simojo]

A chimney breast does not have a DPC, and any damp typically migrates through the brickwork and evaporates away before you notice or mould has chance to grow.

When a breast is removed, its important to deal with the hearth, concrete floor junction, and the sections of wall immediately either side of the beast, or take other precautions to prevent damp coming up where the old beast was.

Can you go into a little more detail with regards to those extra steps you are advising?

 

[^woody^]

You either remove all parts of the existing breast and heath (including sub-hearth), or you insert a physical barrier (DPC, DPM) in whatever parts remain to separate them from the surrounding structure, or you apply a surface coating to the floor and walls to prevent moisture rising and creeping sideways.

 

[blup]

It is the original concrete floor as far as aware, no earlier wooden floor. There is no damp patch, just green fluffy mould that appears from under the skirting. Not a mark on the actual wall itself.

Where the mould is, is on the adjoining wall. There were some issues on the front wall confirmed by a damp person on purchase inspection but this has been solved with lowering the ground level 30 cm, adding gravel drainage channel and then using DPM on inside wall.

Was the hearth removed along with the breast and fireplace.

There may be residual damp in the bricks behind the skirting regardless of the lowering of the outside ground level.

Blup

 

[simojo]

Was the hearth removed along with the breast and fireplace.

There may be residual damp in the bricks behind the skirting regardless of the lowering of the outside ground level.

Blup

The hearth area was chiselled out about 15 mm depth below the concrete floor before the self level put on top (probably not enough as was doing myself and didnt realise it may cause issues). That is my thinking with residual mositure from years of moisture getting down chimney. Think I need to take skirting off, treat any mould, maybe put some damp cream in some holes around the floor and then do my best to proper dry it out with heater and dehumidifier

 

[JohnD]

. That is my thinking with residual mositure from years of moisture getting down chimney.

Hearths are damp because they are in contact with the ground and damp rubble. Yours still is.

Tape a piece of clear plastic tightly to it, see if water droplers form underneath.

Can you lift the laminate?