Climate Conditions And Buildings

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

I often wonder why the same old habitual issues are allowed to reoccur time and time again, as over the past three years I have witnessed first-hand close to 2,000 local homes that were hard to heat.

Mould and damp, health and cost issues are a result of well identified long-term conditions.I fail to understand that education,industry and government bodies don’t seem to grasp that the key factor for homes, especially, is the integrity of their external walls and their ability to keep water penetration to a minimum.If you look towards providing thermal comfort and low energy costs, then local (micro) climate
information must be the foremost consideration Over the past three years I have seen a range of building types with various build materials suffering from excess water penetration in the cavity.

I have recently been to several newly-built (just sold)properties,pre-occupation, where the rain,
wind-assisted, had crossed the cavity to the internal walls (two before it was insulated). This is extreme, and I was astounded by the fact that the water had penetrated across the cavity, not only at floor level but at first floor level as well.On one of these occasions,speaking with the site manager,he expressed concern that there were many of the newly-occupied homes complaining of damp walls. I find this frightening!I have already provided a video of water penetration in the cavity of a new home (pre-insulation) in a previous issue of this magazine which can be viewed online at https://modernbuilder.co.uk These new homes all had similar rustic brickwork, which I believe could be the main cause of the problem, due possibly to the levels of water permeability of the brick material. There seems to be many porous routes on a rustic brick for the rain to penetrate visible to the naked eye.Is this a symptom, or a problem due to builders buying cheaper materials due to the slump, and the recent building crisis?

In several of the new homes, the placement of the weep holes at either side of the every window and door lintel didn’t help matters,allowing wind-driven rain to enter and run down the cavity.
All of the homes with the problem only displayed the water ingress on westerly walls after heavy wind-driven periods of rain from a westerly direction.

Microclimate

This is a major element that needs to be integrated into house design practice. If we look at historical climate information from the Met Office, then our microclimate differences need to be taken on board.
Let’s have a look at the extreme differences this information provides and I believe should be consulted on before a brick is drawn on a plan.West to East in Ireland, the levels of rain, sunshine hours and days of low temperatures are extreme by comparison. In terms of reference, let’s take North Down and Enniskillen areas as reference points for annual comparison:

Rainfall: differences between the two locations in extremes could be as great as 1.5 metres (1,500 mms) of rain fall in a calendar year, in favour of North Down;

Hours of sunshine: between the two locations, in extremes, there could be up to 650 more sunshine hours annually, in favour of North Down;

Days of ground frost: between the two locations, in extremes, there could be up to 115 more days ground frost in the Enniskillen area.

All three of these weather based factors are, in my opinion, major concerns when designing homes in terms of location, materials used, heating needs and weather protection of the fabric.
There has to be a move to address the microclimate effect on our local homes and the detrimental outcomes that householders suffer because of poor design basics.In high rainfall areas is external water proofing of the brickwork an answer? Do we need to apply external weatherproof acrylic renders, impervious treatments for long term protection?

The available hours of sunshine which drive the drying time of the homes needs to be assessed and realistically addressed.Do we just take for granted historically used cavity wall insulation materials and disregard the amount of water saturating the materials in the cavity?The days of ground frost brings with it a range of considerations,where in certain locations, a higher level of insulation specification is needed. This is in addition to adequately detailed, location based heat loss sizing, heating control with weather compensation and other design additions.Surely it’s not rocket science to include local climate considerations into our home design packages for the better good of those in these areas of concern?

“I fail to understand that education,industry and government bodies don’t seem to grasp that the key factor for homes, especially, is the integrity of their external walls and their ability to keep water penetration to a minimum.“

You can contact John Ross at
jross@serc.ac.uk