‘The Top 5 Most Common Paving Issues’ is a guest blog written by Gareth Wilson. Gareth is a multi-award-winning garden landscaper. You can visit his website to learn more about his work.
In my five years as the UK’s leading expert witness in paving, I’ve seen many issues, ranging from minor snags to mind-bogglingly bad installations. However, many common problems occur almost weekly and can be very costly for the contractor if these basic installation guidelines are not followed.
Clients have also become very savvy, asking for advice on Facebook groups, the internet in general, and BS7533:102, now available.
Incorrect Fall: A Common but Serious Paving Error
First and foremost, incorrect fall on the paving is widespread, with many contractors still laying to “the back of the bubble” or, in many cases, especially with porcelain, the paving is almost level. Insufficient fall, especially on porcelain paving, leads to water holding on the surface with surface tension, creating all sorts of slip-related issues, especially in winter. Insufficient fall can also lead to greening or algal growth, especially when installing natural stone or in shady areas.
Loose Slabs: Getting Bonding Application Right
Loose paving slabs are a common issue, and although most landscapers use bonding mortar/primer these days, the actual application is often the issue. A BS7533-approved bonding mortar is the best option and is applied to the back of the paving slabs, not just its centre, as is often the case. The other key point is how thickly it’s used, with many contractors applying a thin layer where the back of the paving slab is still visible. A good guide is 1-2mm for natural stone and concrete and 2-3mm for porcelain. Remove all dust and loose material before application.
Understanding Reflective Staining in Paving
Reflective staining has become a real issue, particularly with sawn products such as Kandla Grey natural stone paving and granite, which are particularly prone to it. Most commonly, this is caused by voids in the mortar bed and minerals migrating through the paving slabs at different rates, where the paving slab touches the mortar bed and doesn’t.
Insufficient Base Depth: A Hidden Cause of Paving Failure
I go to many expert witness cases, and the type 1 base is either insufficiently deep or absent altogether.
Standard practice for a patio base is a minimum compacted depth of 100mm and 150mm for a driveway. Different subgrade types, such as mahl clay, will require a different approach with the guidance in BS7533:102, particularly the heel test.
Breaching Damp-Proof Courses: A Common but Costly Mistake
Breaching damp-proof course regulations in one form or another is common.
Countless times, I’ve seen air bricks completely paved over with a fall towards the house, too. There are some circumstances where breaching the damp proof course is necessary, but there are actions to put in place to mitigate these issues, and they should be followed.
Expertise from the Brett Approved Installer Team
All these issues are too common and avoidable with the proper knowledge, training, and support.
That’s where the Brett Approved Installer scheme comes in.
If you’re a paving contractor serious about raising your game, joining the BAI scheme gives you access to the guidance, resources, and professional network you need to avoid common (and costly) mistakes. It’s more than just a badge – a mark of quality, trust, and a shared commitment to industry excellence.
Contact the Brett Approved Installer team at BAI@brett.co.uk to learn more about joining the scheme.
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