Are you suffering from a domestic shrinkage problem?

Are you contemplating purchase of a new house?  There are increasing numbers of new homes being built in the West Midlands, and if the Times articles on the budget are to be believed, the planning process is about to be freed up, so that even more new homes will be built over the next five years.  In Evesham planning approval has been given for approximately 1000 new homes, and one of the major developers has started to develop their site at a pace. It is amazing how quickly the houses are constructed once the build process starts off.

 It is quite amazing how much water is used in the construction of a house.  We start with mass fill strip foundations.  Wet concrete is poured into these trenches, and once it is set, it is quite unlikely that they will ever dry out. The house is protected from rising damp by the insertion of a damp proof membrane, comprising a thick plastic membrane laid horizontally between two brick courses.

Onto these, the walls are constructed.  The blocks usually are dry, but the builder is still using wet mortar to lay the blocks.  The amount of water present in the floor will depend on the type of construction chosen.  Increasing use of Bison concrete Beams with block infill uses a lot less water than a raft foundation, where liquid concrete is poured into a preformed prepared area. That being said, even the Bison Beam floor will still have a concrete screed laid on top to form a wearing surface.

 One of the problems we have encountered in the past is that in a kitchen area the developer may lay a thin layer of plywood, and onto this they sometimes put a vinyl floor material.  In the property I was asked to look at, the vinyl floor had started to sag, becoming uncomfortable to walk on. When the vinyl flooring was lifted the plywood underneath had completely rotted, to form a soft mush.  As the surveyor looking at this problem, I had concluded that the vinyl flooring had been laid onto the concrete screed before it had had a chance to dry out, the water was trapped and the conditions were ideal for wet rot to develop, leading to a degradation of the plywood. Once the screed had dried out the floor was re-laid, and the problem sorted.

Walls and plastered finishes all use quite large volumes of water, as does paint when it is first applied.  Plaster and paint however normally dry out quite quickly as the surface area to volume ratio is high.  Many internal walls are constructed of stud partition.  Wooden frames are built, being attached to the floor and ceiling. 

Onto this, double skin plaster board is attached with screws. The gap in the middle is filled with an insulation material, and the outer plaster board surface is skimmed with a thin coat of thistle plaster.

If the heating system is run at quite a high temperature level, humidity levels within the house environment will drop quite quickly, when compared to external levels.  This in turn will lead to an increase in the rate of moisture loss within the timber.  As a result the timber will warp and may crack, again resulting in cracking appearing in the plastered walls.

This week, I was looking at a metal baton system supplied by “Walls and Ceilings”. They are a national firm who have created a bespoke system used mostly in commercial buildings.  Both the laterals and uprights are preformed galvanised sheet, which is quite flexible when not fixed.  As soon as the frame work is screwed together, rigidity is created, and the walls become very strong once the plasterboard has been fixed to the frames. 

 The beauty of using a metal framework for the stud wall is that there is no shrinkage or swell with the metal framework, which means that there will be very little movement resulting in very little cracking taking place once the wall has been constructed. Plasterboard joints are taped, using a specialist machine, and the edges of the board are bevelled.  To finish the wall, just six inches of plasterboard either side of the joint are plastered, again reducing the volume of water being applied to the house.

The volume of internal cracking will also vary with the time of year that the house was constructed.  Normally houses built during the summer months will dry out naturally far quicker than houses built during a dull wet winter period.  That being said it always advisable to increase internal temperatures inside a new property gradually over a period of weeks. By doing that you should reduce the incidence of internal cracking taking place. Hopefully that will make the re-decoration work easier to complete, without less preparation work rectifying all those small hairline cracks.

By Tony Rowland. Partner Timothy Lea & Griffiths Evesham