How deep should a recess be?
The standard depth and the times it might differ.
We recently discussed the factors that affect whether you should install your entrance mat into a recess. We also highlighted some of the benefits, including health and safety, cleanliness and mat longevity.
If you have made the decision to go with a recessed entrance mat, there are some things you should know. If you haven’t already, check out our guide on how to install an entrance mat before you try to do it yourself.
Many of us have a more specific question, though: how deep should a mat recess be?
The industry standard for a mat recess depth is 9mm. This is because it suits most standard commercial tiles and adhesives. It is important that you make your recess the right size initially because having to change it later is difficult and expensive.
A recess that is too deep will have to be filled in using a self-levelling compound – usually self-levelling concrete. This is often more expensive than the mat itself as it requires a specialist floor layer on top of all the additional materials.
A recess that is too shallow will need to be deepened, which involves using a jackhammer to dig down before self-levelling. This is even more expensive than filling in a deep recess, as that whole process will follow after it’s made deeper.
Either way, it’s important for keeping costs and time down that your mat recess is the right depth for your mat.
But there are exceptions.
Although 9mm is the industry standard, some mats are considerably thicker. If you are planning to install a coir mat, for example, your recess will need to be about 13mm deep. Coir’s thick fibres make it taller, which means it needs to be set lower to be in line with the floor.
Despite being one of the most popular and effective entrance mats on the market, coir mats’ natural fibres tend to crush over time. As people walk over its surface, the coconut husk crushes and flattens, so will eventually need replacing.
For more information about coir matting, check out this article on how coir mats are good for entrances and the world.
One of the most common problems we see with recesses that are too deep is from people that have had aluminium mats. Aluminium mats are thicker than standard, like coir, but, unfortunately, they are not very effective entrance mats.
The difference between coir and aluminium mats in a recess is that coir entrance mats last and last. They are great mats, so when they are replaced, they will likely be replaced with a similar mat that needs a recess of the same depth.
Aluminium mats, on the other hand, don’t offer much slip resistance, shoe scraping or water absorption. They are one of our most common jobs to remove, so if a mat recess is made for an aluminium mat, it will usually need to be converted to fit a better, thinner one.
How deep should a recess be? A diagram.
See the diagram below for guidance on how deep an entrance mat recess should be.