Climate Change And It’s Raining In The Cavity?

By John Ross, Research Lecturer, and MCS Heat Pump
Inspector for Ireland

With the weather extremes that the country has endured overthe last three months and the likelihood that this may becomethe ‘norm’, there needs to be a serious look at the ability ofwalling materials to counter water ingress through and across the cavities in a home.

Over the past few months I have looked at a number of new homes in different locations, some ready for handover, others occupied – and all had serious damp issues.

The extent of ingress was unnerving in most of the cases, with materials obviously failing to cope with the persistence of the rain, amplified by wind loadings on walls and dubious weepholes either side of window lintels.

In several cases I took the thermal imaging camera where there was a mix of brick types, and thermal differences were noticeable. The temperature profiles showed slight differences in moisture levels within the brickwork. This was probably due to the long wet spell and the persistent wind loadings over such a long spell.

It would seem that the move to rustic, decorative brick may be a part of the reason for some of the ingress. I looked at several different brick types and the face of a brick was quite monolithic, but turning the brick over it reveals a mesh of open cavities i.e. seemingly very porous in nature. In all the inspected cases the issues were on a single elevation, the Westerly direction each time.

This should perhaps set alarm bells ringing with major concerns over the effects of prolonged bad weather on our homes, especially those that are already occupied and have problems. In the range of the occupied homes complaints of damp spots and soiling of decorative materials were common. The extent of the problem is possibly reduced by paint and the fact that the homes are heated.

The enormity of the situation was captured on video in a home by a local insulation company who drilled a 50mm test hole into the internal wall of a home.

The company were having trouble with the bead install and decided to view into the cavity, and the images were incredible. The term it’s raining in the cavity’ couldn’t be truer – with a light inside, water can be seen splashing inside the cavity.

Modern Builder have been given a copy of the video which is available to view in the online version of the publication, on the Modern Builder website at http://www.modernbuilder.co.uk