The short answer
Artificial grass backing is built from two layers. The primary backing is a woven sheet — usually polypropylene — that the yarn is tufted through, giving the rows of stitches you can see underneath. A secondary backing is then coated onto the bottom to lock those tufts permanently in place; this is most often SBR latex, with premium and pet products often using polyurethane (PU). The backing is punched with regularly spaced drainage holes so rain passes straight through to the sub-base. The backing matters because it controls how well the tufts are anchored, how stable the grass stays in heat and cold, and how quickly water drains — a fully PU backing tends to be more dimensionally stable and faster-draining than a perforated latex one.
Most people judge artificial grass by its blades, but the backing decides how long it lasts and how well it drains. Flipping a sample over and reading the spec for the backing type tells you a lot about quality.
Backing at a glance
- Primary backingWoven polypropylene
- Secondary backing optionsSBR latex or polyurethane
- DrainagePunched holes in the backing
- Latex backingCommon, cost-effective
- PU backingMore stable, faster-draining
Primary backing: where the blades are stitched
The primary backing is the layer the yarn is tufted through. It is typically a woven polypropylene cloth — sometimes a double or triple weave on better products — that gives the grass its grid of stitch rows and its basic shape. Look at the underside and you will see the neat lines where each tuft has been stitched in.
A stronger, multi-layer primary backing resists stretching and tearing during installation and over the lawn's life. Because the yarn is only stitched through this layer, the primary backing on its own would let tufts pull out — which is why a second layer is needed to lock everything down.
Secondary backing: latex versus polyurethane
The secondary backing is a coating applied to the underside to bind the tufts permanently. There are two main types, and the difference is a genuine quality marker:
- SBR latex: the most common and most cost-effective coating. It does the job well for most domestic lawns, locking the tufts firmly. Its main limitations are that it can be slightly less dimensionally stable in extreme temperature swings and that drainage relies on the punched holes.
- Polyurethane (PU): used on premium and many pet-friendly grasses. PU tends to be more dimensionally stable (less prone to expanding, contracting or rippling with heat and cold), often drains faster, and is sometimes preferred where pet urine and frequent washing are involved because it does not absorb liquid in the way latex can.
Both are valid; the right one depends on budget, drainage needs and whether pets use the lawn. A latex-backed grass is perfectly suitable for many gardens, while PU is the upgrade choice for demanding situations.
| Backing type | Strengths | Typical use |
|---|---|---|
| SBR latex | Cost-effective, firm tuft lock | Most domestic lawns |
| Polyurethane (PU) | Stable, fast-draining, hygienic | Premium and pet lawns |
Indicative comparison. Product quality varies within each type.
Drainage holes and why they matter
For rainwater to clear, the backing is punched with drainage holes at regular intervals across its area. Water passes through these holes, into the sub-base of compacted aggregate beneath, and away — which is why a well-prepared free-draining base is as important as the grass itself.
The pattern and number of holes affect drainage speed. Perforated latex backings drain through their holes; some fully permeable PU backings let water through across the whole surface, which can help on flat sites or where heavy rain pools. For most UK gardens the standard perforated backing copes well as long as the base below is free-draining and laid to a slight fall.
If a lawn is for dogs, faster drainage and a hygienic backing become more important, because urine and rinsing water need to clear quickly. This is one reason pet-specific grasses often pair a PU backing with extra or larger drainage holes and a free-draining sub-base.
How the backing affects durability and fitting
The backing has a big say in how long a lawn lasts and how easy it is to install well. A strong, stable backing keeps the grass flat and true through years of temperature swings — the expansion and contraction that comes with hot summers and cold winters is exactly what can cause a weaker backing to ripple, wrinkle or develop a wave across the surface. This is one of the main reasons premium grasses favour polyurethane: its dimensional stability means the lawn is less likely to move after it is laid.
Backing quality also shows up during fitting. A robust multi-layer backing:
- Resists tearing when the grass is pulled, trimmed and pinned, so edges and seams stay clean.
- Holds pins firmly around the perimeter without the backing splitting.
- Takes adhesive well at seams and on hard surfaces, giving a strong, lasting bond.
- Lies flatter straight off the roll, needing less time to acclimatise and settle.
For households with pets, the backing matters even more. Frequent rinsing and dog urine mean the backing is regularly wet, so a non-absorbent, fast-draining type keeps the lawn hygienic and stops residues lingering in the material. A latex backing can be perfectly suitable for a typical garden, but where heavy washing or pets are involved, the case for polyurethane strengthens.
When comparing products, ask the supplier which backing each uses, whether the secondary coat is latex or PU, and how drainage is achieved. Two grasses with identical-looking blades can perform very differently over a decade purely because of what is on the underside — the part you never see but rely on completely.
It is also worth knowing how the backing influences disposal and environmental claims, since this comes up increasingly often. A grass with a single, separable backing material is easier to recycle than one bonded from mixed plastics, and some manufacturers now offer fully recyclable polyethylene or polyurethane backings as a selling point. While recycling routes for artificial grass are still limited in the UK, a cleaner backing construction at least keeps that option open at the end of the lawn's life, rather than leaving disposal as the only choice.
Frequently asked questions
Which backing is better, latex or polyurethane?
Polyurethane is generally the higher-spec option — more dimensionally stable, often faster-draining and well suited to pets and frequent washing. Latex is more common and perfectly adequate for many domestic lawns at a lower cost. The right choice depends on budget, drainage needs and whether pets use the lawn.
Does artificial grass backing let water through?
Yes. The backing is punched with drainage holes so rainwater passes through into the sub-base below. Some polyurethane backings are fully permeable across their whole area. For drainage to work, the grass must sit on a free-draining base laid to a slight fall, not on solid impermeable ground.
Can the backing be damaged?
The backing is durable but can be cut, punctured by sharp objects, or weakened if the grass is laid over an uneven or poorly compacted base that lets it flex repeatedly. Latex backings can also be affected by prolonged standing water. A good base and careful handling during fitting protect the backing for the long term.
Sources & further reading
Figures on this page are typical UK ranges drawn from published cost guides and are intended as guidance, not a quotation.