Floorboards and Joists on show

How Thick Are Floorboards?

Floorboards are a common sight in UK homes, although not used in new builds anymore, if you have an older home you will probably have floorboards. If you ever need to replace then you will no doubt need to know how thick they are, or indeed, how thick they should be.

How Thick Are Floorboards?

Floorboards are generally either 18mm, 21mm or 25mm thick.

21mm will be the more common size. Sometimes you will see 18mm & 16mm boards but these tend to have a lot of flex which is why they aren’t used too much.

A general rule of thumb is the wider your floor joists are apart the thicker your floorboards will need to be.

Thicker floorboards are stronger and are much less likely to sag, bend or even break across larger spans.

A more modern alternative to floorboards is chipboard sheets, these sheets are nearly always used in new buildings as they are easier to lay and more cost-effective. The age of the floorboard is over!

These sheets are 18 or 22mm thick as standard.

Floorboards and Joists on show
Floorboards and Joists on show

Why not just go for the thickest possible then?

Well, the simple answer is cost. The thicker the floorboard the higher the cost. and floorboards are already an expensive way to lay a floor, hence why all new builds now use chipboard instead.

So adding extra cost isn’t wanted, which is why people often use the thinnest floorboards they can get away with. this comes with its own problems, mainly in the strength department.

What wood are floorboards made from

Most floorboards used in the Uk will be from spruce or pine. These are the more common woods used although sometimes other softwoods like fir may be used. The trees are often slow-grown which can increase the strength of the wood.

Replacing Floorboards

When replacing floorboards and patching the floor it is crucial that you get the correct depth of floorboard. Even small differences in the thickness of your floorboards will be visible through even a thick carpet.

I have seen this done before and trust me, there is no hiding it. Take that little bit of extra time to measure your floorboards and buy the correct thickness.

Older Floorboards

Older houses can sometimes have huge floorboards that are twice the width of modern floorboards. When it comes to these the thickness can be anything really. if you want to replace one of these bad boys then you are probably looking at having to get a plank custom cut down, which comes with its own expense. You don’t really see these sold anywhere.

Sam Wood

Wood by name, wood by nature. I am a fully qualified, time-served, award-winning joiner with an NVQ Level 3 in Carpentry and Joinery as well as an HNC in Construction. Beyond my joinery qualifications, I have also earned a degree in building surveying. I believe these qualifications make me perfectly positioned to provide expert advice on many different areas of DIY as well as share all of the tips I have picked up in over a decade working on building sites!

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