Many flooring disputes stem from confusion between flatness and levelness. Richard Renouf explains why the two are different and why it matters
IN our last article we considered how to assess whether or not a subfloor is flat. This is the third of the four basic requirements (sound, smooth, flat and dry) but there is a fifth characteristic that some people add, and that’s often misunderstood. Flat means free from undulations and surface irregularities. But does a subfloor need to be level? Unless this is a specific requirement for a particular job, the answer is no.
There are situations where the floor cannot be level, but still needs to be free from undulations, the most common being ramps, especially when required for wheelchair users. Sometimes the use of the room dictates that the floor must be level, such as when there is delicate equipment – I’ve had to assess operating theatres, MRI scanning facilities, radiotherapy rooms and computer laboratories. In these cases the requirement will be set out in the specification.
Assessing level is very similar to assessing flatness, which we covered last time. It can be done with a two-metre spirit level, but this must be checked for accuracy on a known level surface to avoid misleading readings. A laser level and a dipstick is probably a better option as it can be used over a much larger span and avoids compounding slight inaccuracies when reading the bubble of a level repeatedly over large areas and in different alignments to ensure the floor is level and flat in all directions.
If a floor isn’t level or flat, a user may notice this because they find seating, desks and other furniture wobbles. However, a lot of furniture items – including billiard tables and games machines – have adjustable feet that can be used to make them stable and level even on uneven floors. Many chairs have frames which are flexible enough to adapt to reasonable unevenness in the floor when they’re sat on.
I was asked recently to look at an uneven subfloor because the customer’s settee rocked slightly. After a brief conversation I sent her some thick felt pads and asked her to try them as it was cheaper than having me go out, and then possibly having a dispute with the flooring contractor. She rang me the day after she received them in the post and was absolutely delighted they’d made the settee stable and for her the issue was now resolved.
For the flooring inspector there is another factor to consider. A recent inspection found a flat subfloor, free from undulations, but with a drop off of about 25 mm from the front to the back of the office. The client felt that the contractor should have made the floor level, not least because they had referred to the use of a ‘self-levelling compound’, rather than the correct term of ‘smoothing compound’.
The client was adamant he wanted the flooring lifted and the subfloor made level. When it was pointed out that to do this would mean problems with the doors, skirting boards and other features in the building the client admitted this was an unreasonable expectation.
Bubbling and lifting flooring can affect the regularity of the surface of flooring and so I always make sure I take readings at arm’s length and also when standing on the flooring right next to the gauge. This means any movement due to gaps under the flooring can be identified and measured to help when diagnosing issues.
So far, we have looked at assessing smoothness, soundness, flatness and its lesser twin, level. In our next article we’ll begin to look at the subfloor issue that causes more problems than anything else. Don’t miss the next part of our series.
www.richard-renouf.com
Richard Renouf is an independent flooring consultant
