Quick answer: On a microcement floor, the fibreglass mesh goes into the self-levelling compound, not into the microcement. Lay the mesh down, pour the self-level over it, let it dry, prime, then apply your two coats of microcement. If the mesh ends up in the microcement instead, it will show through two coats, so you need a three-coat system to bury it.
This one came up twice on our phones last week. One caller was planning a new kitchen-diner floor and wanted to know what goes under the microcement. The other had already started: their builder had bedded the mesh straight into the first coat of microcement, and after two coats it was still showing through. Nothing had gone wrong with the material. The mesh was simply in the wrong layer.
So here is exactly where the mesh goes, why, and what to do if yours is already showing.
| Quick facts | |
|---|---|
| Where the mesh goes | In the wet self-levelling compound, before any microcement |
| Order of layers | Sound floor → mesh + self-level → primer → microcement coat 1 → coat 2 → sealer |
| Mesh in the microcement? | Then you need three coats, not two |
| Floor kit | 5m² £220.50 or 10m² £333 inc VAT, mesh, tape, primer and sealer included |
| Self-levelling compound | Not in the kit. Buy a standard one from a builders’ merchant |
| Difficulty | Moderate. The prep is the hard part, not the microcement |
What is the fibreglass mesh actually for?
Microcement is a thin decorative finish. Two coats come out at roughly 1–2mm, so it can’t add strength to a floor or hold a weak one together. The mesh is there to reinforce the layer underneath it. Set into a self-levelling compound, it turns that compound into a stiff, flat reinforced plate. That plate spreads out small stresses from the floor below, so hairline movement is far less likely to telegraph up into your finish.
That’s why it belongs low down in the build-up. Its job is in the base, not the top coat. Our guide to whether microcement floors crack goes into the movement side in more detail.
Microcement FLOOR Kit · from £220.50 inc VAT
Best for: screed and concrete floors. Includes the mesh roll, mesh tape, primer, two-coat microcement and sealer
View product →Where does the mesh go, step by step?
Here is the order we give everyone who rings us about a concrete or screed floor:
- Check the floor is sound. It needs to be structurally stable, clean and dry, with no movement or flex. Fix anything loose before you go any further.
- Roll out the fibreglass mesh. Our lay-flat mesh comes on a metre-wide roll and sits flat straight off the roll. Lay it across the floor.
- Pour the self-levelling compound over the mesh. The mesh should end up embedded in the wet compound, not sitting loose on top of it. Follow the compound manufacturer’s instructions for mixing and depth.
- Let it dry, then knock back any high spots. A light sand once it’s dry gives you a flat base.
- Prime. Apply the Concrete Lab primer from your kit and let it dry.
- Tape joints and transitions. Use the self-adhesive mesh tape over any joints, changes of substrate or thresholds.
- Apply microcement coat one, thin and even. Let it dry and sand lightly.
- Apply microcement coat two, the finishing coat for colour and depth.
- Seal with Concrete Lab Sealer. Its 7-day full cure is when the floor reaches full stain resistance and durability.
Done this way, the mesh is buried well below the surface before you open a tub of microcement. Two coats is then plenty.
Lay-Flat Fibreglass Mesh · from £3.00 inc VAT per metre
Best for: extra mesh for larger rooms or overlaps. Alkali-resistant and lays flat off the roll
View product →Do I need self-levelling compound at all?
Usually, yes. The only time we’d say you can go straight onto a concrete floor is when it’s a brand-new screed that’s completely flat, with no hairline cracks. Most floors in real renovations aren’t like that. Walls have come out, old adhesive has been scraped off, and there are patches and cracks. A meshed self-level gives you a fresh, flat, reinforced start.
If you’re working over timber or tiles rather than concrete, the prep is different. Get in touch before you start and we’ll talk you through it.
Why does the mesh show through my microcement?
If the mesh has been bedded into the microcement itself, the weave sits right at the surface. Microcement goes on in very thin coats, so the pattern is visible after the first coat and often still after the second. You can’t fix that by trowelling thicker. Thick coats crack and use up material fast.
The fix is a third coat. That’s why our 3 Coat Pack exists. It’s the system we use for “difficult” areas where mesh has to go into the microcement layer, and it’s part of our wall tile kits for the same reason. The third thin coat buries the weave and gives you a clean finish.
One customer’s tip on getting the mesh right when it does go into the microcement:
“I would however recommend making sure the mesh lies absolutely flat and preferably stuck down to primer under the first coat as it is prone to ‘floating’ and rippling otherwise.”
Richard B. · verified Judge.me review
Microcement 3 Coat Pack · from £36 inc VAT
Best for: areas where the mesh goes into the microcement, and covering existing tiles
View product →My builder already put the mesh in the microcement. What now?
Don’t panic, and don’t pile on thick coats to hide it. Stop, take some clear photos in good light, and send them to us. In most cases the answer is to sand back lightly and apply a further thin coat (or two) over the mesh to bring it up to a three-coat build. We’ll tell you how much extra material you need for your area. Please don’t guess. Over-ordering wastes money, and stretching too little material too thin is how the mesh ends up showing again.
It also helps to send your builder the kit instructions before they start. Most installers have used other microcement systems, and the build-up varies from brand to brand.
How do I apply the first coat over the primed base?
Once your meshed self-level is down and primed, the microcement part is the same as any other surface. This video shows the first coat going on:
Concentrated Universal Concrete Primer · from £12.50 inc VAT
Best for: priming the dried self-level, and top-ups on bigger floors
View product →Planning the whole floor? Read can you DIY microcement floors, check underfloor heating compatibility, and use our area calculators to choose between the 5m² and 10m² kits.
Frequently asked questions
Does the fibreglass mesh go in the microcement or the self-level?
In the self-levelling compound. Lay the mesh, pour the self-level over it, then prime and apply microcement once it’s dry.
How many coats of microcement do I need if the mesh is in the microcement?
Three. The mesh shows through after the first coat and often the second, so a third thin coat is needed to bury it.
Is self-levelling compound included in the floor kit?
No. The kit includes mesh, mesh tape, primer, two-coat microcement and sealer. Buy a standard self-levelling compound locally.
Can I skip the self-level on a concrete floor?
Only if it’s a new screed that’s completely flat with no hairline cracks. Most renovation floors benefit from a meshed self-level first.
Should I put mesh tape on joints as well?
Yes. Use the self-adhesive mesh tape over joints, thresholds and changes of substrate after priming.
Can I hide visible mesh by applying a thicker coat?
No. Thick coats crack and use material fast. Sand lightly and add a further thin coat instead, and send us photos first.
Still not sure what your floor needs? We’re happy to talk you through it – info@concretelab.co.uk
