Get talking: A modern Victorian

Materials World magazine
,
1 Jul 2018

Is it time to change how we build houses considering the widespread condensation problems in modern homes, asks Ken Tailby.

If we think about the associated health risks caused by condensation problems in housing, maybe our current building techniques are not fit for purpose.

I tried to research and find the point at which condensation becomes a problem in our homes. As far as I can tell, this is a fairly modern problem and may be a result of our lifestyle changes, insulation, and drought proofing.

So, if we look back at late Victorian properties, did they have condensation and mould problems on the same scale that we endure today? I don’t think they did.

These houses were built with solid walls, pitch roofing without sarking felt and an open fire in every room. Windows were made of wood as were the external doors. The result would have been lots of drought, incoming fresh air and lots of passive ventilation via the chimney flues.

However, I expect the houses were quite cold, hence the need for warming pans. Clothes and bedding would be washed less frequently and dried by hanging on a rack in the kitchen with a large coal fired range, producing lots of heat, but also drawing in moisture laden air up through the flue.

Learn from the past

So, let’s look at lessons we can learn from this lifestyle and see if there is anything to be gained from it.

One of our modern methods is to build a completely sealed house, and then rely on motorised ventilation to control the humidity. This might be ok for a spacecraft, a nuclear bunker, or a submarine, but seems to be a failure when it comes to residential homes.

It just takes one power cut or blocked filter to render the system redundant and the house to suffer from horrendous damp problems.

In my opinion, the best option lies somewhere between these two extremes.

Our modern lifestyle produces lots of moisture vapour. We breath, we sweat, shower, wash and dry clothes, cook, keep animals in the house, and we come in from the rain.

The air changes in the house have to cope with all this moisture. It’s no wonder condensation occurs and moulds germinate. In my experience, microclimates are created all over the house – the temperature differentials may be tiny but just enough to cause a dew point to be reached and condensation to occur.

This can be seen for example behind wardrobes, inside the kitchen units, and behind large settees. Of course, cold bridging is also a problem and can sometimes be seen on the ceiling, wall junction, and window reveals.

My proposal is for us to return to some of the best features of the Victorian build combined with modern techniques available today.

Firstly, install a passive vent into each wet area, also containing a positive input unit. Secondly, dry clothes outside or with a tumble dryer vented to the outside – condensation dryers are a big source of moisture vapour once the exchange element is covered with fluff. And lastly, build a good-sized entrance porch with a constant duty extract for wet clothes and boots.

The house must be able to provide adequate air changes to cope with the expected moisture. 

I am sure that there is a formula already in place for this kind of calculation.

It would be interesting to see the amount of moisture produced. I hope that this is of interest and provides some food for thought.

Ken Tailby, AIMMM, CTIS, CSSW, has been in the remedial treatments industry for around 50 years. Starting with the Special Services division of the Heelas of Reading, then joining Rentokil as a technician and surveyor. He started his own business, Timber Treatments in Guernsey, in 1979. He continues to be involved in the day to day running of his business and still undertakes property inspections