Check-out Your Ground Floors

The next step in my maintenance and retrofitting journey is to investigate the state and condition of my ground floors i.e. those floors and walls that are in close contact with the ground.

Checking your Ground Floors

Solid floors are benign but can be cold and damp. If you have timber floors at ground level checking their condition is critical. Damp rises up from the ground into the masonry, rain wets the exterior walls and moisture from the inside of your home all add to the water within the fabric of your building. Timber at ground level or close to wet masonry is susceptible to getting wet. Damp timber will, over time rot. Wet timber in an unventilated or poorly ventilated floor void will rot. Wet rot can lead to dry rot.

Solid Ground Floors

If you think all or some of your ground floors are solid try the jump test. If it is a solid floor there will be no bounce when you jump up and down on it. Masonry and particularly concrete is pretty good at dealing with damp but without a barrier (commonly known as a DPC or damp proof course) damp will rise up into the masonry making any timber in contact with it damp. Damp walls will also add to humidity and moisture within your home.

Suspended Timber Ground Floors

Many of our homes are finished with carpets, tiles, laminate flooring or engineered wood and it can be difficult to determine whether the ground floor is suspended or solid. If like me you have the exposed original floorboards, the gaps between them and the draught coming up tells you that they are suspended.
If you don’t know, try the jump test. If you get some bounce this indicates the floor may be suspended but it could be a timber floor over a solid floor.
Is the floor warm or cold to the touch? A solid floor with ceramic tiles will feel cold but an engineered timber floor finish whether solid or suspended will feel warm so it can be difficult to tell.
Go outside and see if there are air bricks in the exterior walls, you should have them at the front, the side and the back. They are the best indicators that you have a suspended timber ground floor.
If you cannot find out, go to your neighbours and ask them. If you houses look the same it is likely the floors will be the same construction.

What’s the condition of your Suspended Timber Floors?

If you have air bricks in the exterior walls do you have them at the front, the back and at the side? You need this for adequate through ventilation.
Have the air bricks been covered over or blocked up by previous works? Is there excessive bounce or worse still, is part of the floor is dropping?
What about the smell? Damp rooms usually have a distinctive and easily recognisable smell.
Are the floorboards or skirting boards damp? Or to put it in technical terms, is the moisture content of the wood at a level where decay will start? At a moisture content of 20% or more wood will start to decay.
You can buy a basic ‘mini moisture meter’ for less than £15 from Tool Station– much less than dealing with an outbreak of dry-rot.

Moisture Content of Wood

Timber with a moisture content below 15% is generally consider to be safe.
Timber with a moisture content between 18-25% is at risk.
Timber with a moisture content above 25% is considered to be already decaying

We all tend to ignore parts of our home that we cannot see, preferring to spend money on visible illustrations of our taste and aspirations. We are all required to keep our cars in good condition, maybe a ‘home MOT’ looking at parts of our home that need maintenance would encourage us to focus on those areas we ignore. We should perhaps spend money on maintaining the essential fabric of our homes then consider the aesthetics and the fancy bits.

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Please note this is a guide and is not a definitive source of technical and/or legal information.

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