New Way of Damp Proofing


Property Remedial Articles - Olympic Construction

Who says that you can’t learn something  about damp proofing everyday?

Last week I went out to undertake what I assumed was going to be a straight forward damp survey. Everything looked normal from the outside, standard brick walls and tile roof, with no defects.

When I moved onto the inside I was surprised to be getting very low readings on all walls with very little or no deflection, from the walls or skirtingboards. (12%wme)

I suspected that something was amiss or I was missing something, as the readings didn’t register with the impressions on the carpets as a result of were the furniture once stood, or the shading to the paintwork on the walls.

You always get some differences within the walls and rooms of the property but this dose not mean its affected by rising dampness.

On further investigation I established that the internal walls of the property were of cement based strawboard {30mm). These where fixed to a steel frame and sat on a thick bitumen damp proof course.

The steel frame was protected from dampness, from the external elevation by a strip of ‘Denzo tape’ which ran the full height of the building.

The base  of the cavity was infilled with cement and benched to the outside elevation which was drained through vertical weep holes within the external elevation.

Photograph showing internal view of the cavity and wall construction.

I have to say that this is a fantastic design, especially when the cavity is filled with ‘cavity wall’ insulation, no mortar dropings  blocking the cavity, resulting in bridging of the d.p.c. and what would appear to be an even distribution of heat across the internal elevations, reducing the effects of condensation.

I can see some flaws in the design though,  it would  a whole new ball game should renovation works be required. As you cannot sink wires and pipes into the plaster, or simply cut an opening, as this would distroy the wall boards.

And I would like to know what the sound proofing was like on a busy road, as this property was located within a cul-de sac.

Also what would happen should there be a water leak?

Has anyone come across this type of design before and can you shed some light on the points raised?

But the main point for the client is that the property was free from dampness, and so he was happy and I got paid on the day.

Adrian Dawson

Olympic construction Ltd