Screed with fibres
Fibre-Reinforced Screed Floors
Fine fibres mixed through the whole screed, controlling shrinkage cracking and toughening the surface — the standard approach on most floating and unbonded floors.
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Fibre screed is liquid screed with fine synthetic or steel fibres mixed through it. The fibres run through the whole depth of the screed rather than sitting in one layer the way mesh does, and their main job is to control the fine shrinkage cracking that can appear as a screed dries.
For most domestic and light commercial floating and unbonded screeds, manufacturers specify fibre dosing as the standard approach, so a fibre-reinforced screed is what most of those floors already are. Where a structural engineer's design calls for mesh or heavier reinforcement, that is a different specification.
This page explains what the fibres do, when a screed with fibre is the right call, and when a screed without fibres is perfectly adequate. For the technical detail, see fibre-reinforced liquid screed.
What the fibres do
- Control plastic shrinkage cracking while the screed is drying
- Improve impact and abrasion resistance across the whole floor
- Work at a micro scale through the full cross-section of the screed, not just at one level
- Are dosed into the mix at batching, so there is nothing extra to position on site
Fibre screed vs mesh reinforcement
Fibre reinforcement
- Mixed evenly through the whole screed
- Controls shrinkage cracking and surface wear
- No sheets to cut, lap or position
- Standard for most domestic floating and unbonded screeds
Mesh reinforcement
- A steel mesh placed at a set height in the screed
- Resists tensile forces from bending
- Specified by an engineer where the design needs it
- Adds setting-out and fixing time on site
Screed with fibre or without
A screed without fibres is not a faulty screed. Many bonded domestic floors have been laid plain for decades and perform well, because a bonded screed is held by the slab beneath it. Fibres earn their keep most on floating and unbonded build-ups, where the screed sits on insulation or a membrane and has to manage its own movement as it dries.
The right answer comes from the screed manufacturer's design guidance for the build-up, not from a blanket rule. Our fibre-reinforced vs mesh screed comparison goes deeper, and the sand and cement screed page covers the traditional hand-laid alternative.
How a fibre screed pour runs
- 1
Dose at batching
The fibres are measured into the mix at batching so they are distributed evenly.
- 2
Pump as normal
A fibre screed pumps, flows and is dappled exactly like any other liquid screed.
- 3
Same aftercare
Drying, ventilation and first heating follow the same rules as any liquid screed floor.
Where fibre screed is used
Fibre-reinforced liquid screed shows up most often on floating floors over insulation, on unbonded build-ups over a membrane, and on underfloor heating floors where the screed encases the pipes. These are the situations where the screed has to manage its own drying movement without help from a bonded slab below, and where the fibres' shrinkage control earns its place.
On larger commercial pours, fibres are common too, though the final say on reinforcement there sits with the engineer's specification rather than with a general rule of thumb.
Frequently asked
Not sure whether your floor needs fibres?
Send the build-up — bonded, floating or over heating — and we will confirm the right mix. We reply the same working day.