Water Damage, Condensation & Sideways Penetrating Damp

rising damp cumbernauld

The building


The Problem

A semi-detached house in the greater Glasgow area in Cumbernauld.

The house was located on a hill, so some of the rooms were partially underground. The house felt damp.

The customer has been told previously that the house has rising damp and needs a new damp proof course. She called us for a second opinion.

The Findings

One of the bedroom sidewalls looked and felt wet from inside and plaster was damaged at the bottom. There was heavy black mould infestation in the lower right corner.

Outside in the back one of the drainpipes was missing and the wall gradually got saturated with water.

mould_infestation

Mould infestation

back

Missing gutter on the back wall

The wall scanner revealed dampness on the external wall especially next to the bedroom window. Because the wall was a cavity wall with no cavity insulation, I have scanned for moisture from both externally and internally.

To determine the moisture distribution, the walls have been scanned with a deep scanning wall scanner and the results are shown below.

The bedroom wall scan from inside shows rather low moisture values (dark blue areas), with small scattered moisture spots (lighter areas), however overall this wall is dry. (The grey area from the scan is the area covered by the wall-mounted TV.) There is NO evidence of rising damp here. The cause of black mould in the bedroom along the skirting board where the wall is the coolest was condensation.

Internal wall scan

Bedroom wall scanned from inside

External wall scan

Bedroom wall scanned from outside


The wall scan from outside reveals much higher moisture values (light blue to orange) than the internal scan. The moisture values are the highest along the left hand side, in the close vicinity of the missing downpipe, where the rainwater has fully saturated the wall. There are also high moisture values alongside the bottom section of the wall due to splashed rainwater.

In addition, the back bedroom wall, situated under the street level, hidden behind a large walk-in closet was also wet. This wall had plasterboard insulation, so visually looked OK, however the spot checks through the plasterboard with the deep penetrating wall scanner revealed very high moisture values, indicating here a combination of rising damp and sideways penetrating damp.

Recommendations

To remedy the situation, to dry out the walls, to handle the mould and condensation problem, and to restore a healthy living environment in the building, the following actions were recommended:

1. Downpipe: the missing downpipe has to be replaced ASAP and all gutters must be inspected for further leaks and fixed.

2. Condensation and mould problem:

- Wallpapers must be removed from the bedrooms as they are non-breathable and facilitate condensation.

- The walls should be painted with lime or mineral based paint (not emulsion paints, which are non-breathable). This is a natural alternative to the use of chemical paints or chemical anti-mould paints.

3. Wall dampness problem: after the replacement of the missing downpipe the bedroom walls will gradually start drying out. This is a slow process, which can take a year or longer, depending on several factors such as: brick type, wall thickness, moisture saturation, temperature (both internal and external), the amount of heating etc. The earth touching back wall however will stay wet or even worsen as the wall’s vertical insulation keeps decaying as time goes on. To speed up the dehydration of the walls and to also handle the moisture problem in the back earth-touching wall, the installation of an Aquapol Masonry Dehydration System was recommended.
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