Independent comparisons. We may earn from shop links. More info

Hot tub ground mat

Updated: 21.10.2026

You want something under the Lay-Z-Spa so the patio is not scratched and the bill drops. A hot tub ground mat can only be an abrasion layer, and it does not cut heat loss unless it is the foam protector the maker sells for that purpose. The filled spa weighs the water. A felt disc here does not subtract that weight, and none of the felt listings states an insulation figure. The pads are on the [pool pad comparison](/hub/pool-care/pool-pad). The Miami figures below are Lay-Z-Spa’s two published weights, not an average and not a structural calculation. A purchase can earn a commission at no extra cost to you.

You want something under the Lay-Z-Spa so the patio is not scratched and the bill drops.

Our top picks

TIHOOK TIHOOK felt pad 400 x 400 cm

Best overall

TIHOOK TIHOOK felt pad 400 x 400 cm
7.4/10about £21.19
View offer
YISIZES YISIZES PE cloth 274 x 274 cm

Best value

YISIZES YISIZES PE cloth 274 x 274 cm
6.8/10about £9.99
View offer
YumSur YumSur felt 4 m, 300 g/m²

Alternative

YumSur YumSur felt 4 m, 300 g/m²
5.4/10about £33.99
View offer
On this page
  1. 1.The spa weighs the water, not the mat
  2. 2.Decking, grass, and a flat base
  3. 3.Their foam protector and these felt discs
  4. 4.What UK reviews say about thin felt

The spa weighs the water, not the mat

Lay-Z-Spa’s setup page gives the Miami AirJet 696 kg filled before anyone climbs in. The FAQ gives 669 kg for the same model, again before users. Use the manual, not a midpoint. An older manual lists about 1,100 kg and 1,973 kg for larger models. The heaviest felt pad here is 4.6 kg. It does not move 669 kg or 696 kg, and no pad states a structural rating. The mat is a surface layer. The water is the load.

Decking, grass, and a flat base

Most standard UK garden decking is not designed for that filled weight, which is Lay-Z-Spa’s own FAQ. A mat does not redesign the joists, so have the deck checked before you fill. Grass is allowed only if it is level, and the grass will be damaged. Do not fill while one side is low. The laying order is how to lay a pool ground cloth. You also need a grounded socket with an RCD within about 7 m, and no extension lead.
TIHOOK TIHOOK felt pad 400 x 400 cm

Testsieger

TIHOOK TIHOOK felt pad 400 x 400 cm
7.4/10about £21.19
View offer

Their foam protector and these felt discs

The heat-loss sentence belongs to Lay-Z-Spa’s foam protector, not to the felt ASINs here. BW60309 is £39.99, ten pieces, 2.16 m by 2.16 m, except the Mauritius AirJet. A round protector is £66.99 for spas up to 211 cm. The 10-piece set is from £35.04, 4.4 from 6,666 ratings. Felt of 1.8 mm to 2.3 mm in other shops is not stated here, and neither is an insulation figure. Buy the foam for the maker’s heat story if your model is listed. Buy felt as a measured layer on a hard patio. A 2.16 m square is smaller than a 4 m disc. The material split is the PE ground cloth or felt pool mat page.

What UK reviews say about thin felt

The £22.99 YumSur is described as a thin pad that rolls up, and one buyer says not to use it under a hot tub. Its size line says 15 cm against a 3.05 m bullet. The 300 g/m² pair shares two UK texts, cushioning without curling and felt thinner than expected, so count them once. KEAGAN’s mat notes, inside 3.6 from 89 ratings, say thin felt and stones, and one buyer binned it for the smell against a 500 g line on an 18 ft title. TIHOOK’s two texts are shared with the 370 cm round.

Common questions

Can I put a Lay-Z-Spa on the lawn?
Yes, if the ground is flat and level, which is Lay-Z-Spa’s own condition. The grass will be damaged. A felt mat does not prevent that, and it does not level a hollow. You still pick out stones, because thin-felt reviews say you can feel them through the pad. The filled weight is still the figure in the manual for your model, before the people who climb in.
Will a felt mat protect decking?
It may stop light scuffing on the boards. It does not make standard UK garden decking strong enough for the filled spa. Lay-Z-Spa says most of that decking is not designed for the weight. Have the deck checked for the kilograms in your manual before you fill. A mat is not that check.
Does any pad in this comparison save electricity?
No insulation figure is stated on the felt or PE listings in the set. The heat-loss claim is attached to Lay-Z-Spa’s own floor protector, the foam tiles sold from about £35.04 on the best-seller list, at £39.99 for BW60309, and at £66.99 for the round protector for spas up to 211 cm. A felt disc is an abrasion layer you measure, not a substitute for that foam set.
Why do two official pages give two Miami weights?
The setup page says 696 kg before users. The FAQ says 669 kg before users for the same model. They are both Lay-Z-Spa pages and they disagree. Take the filled weight from the manual for your model year. Larger models in an older manual are around 1,100 kg and 1,973 kg. The mat’s own weight, a few kilograms, does not explain the gap.
Is a 2 mm felt enough on a stone patio?
Shops elsewhere sell felt around 1.8 mm to 2.3 mm. That thickness is not stated on these ASINs, so a YumSur or TIHOOK listing has not promised you 2 mm. UK reviews on the 10 ft YumSur and on KEAGAN say the felt is thin and that stones come through. On a stone patio you still need the surface clear, and you need a size line that agrees with itself before you rely on the disc.
Do I need an electrician?
You need a grounded socket with an RCD within the cable run, about 7 m on the Lay-Z-Spa FAQ, and you must not add an extension lead. If no such socket is in reach, an electrician has to provide one. The mat does not change the electrical rules. One metre of clearance around the spa is a siting rule from the same guidance, not a felt specification.

Related pages

Pool pad buying guide

Pool pad

Best pool ground cloth UK: who should skip a thin sheet

How to lay a pool ground cloth, then stop the fill

PE ground cloth or felt pool mat: choose one claim

Sources

Public UK sources for ground preparation, filled-spa weight, product safety, and the shallow-fill check, taken from the research digest. Listing prices, stars and review counts are from amazon.co.uk on 19 October 2026.

  1. Bestway UK — how to prepare the ground for a pool (retrieved 19 October 2026)
  2. Bestway — 16 ft ground cloth (retrieved 19 October 2026)
  3. Lay-Z-Spa — setup essentials (retrieved 19 October 2026)
  4. Lay-Z-Spa — FAQ (retrieved 19 October 2026)
  5. GOV.UK — General Product Safety Regulations 2005, Great Britain (retrieved 19 October 2026)
  6. Consumer Rights Act 2015, section 9 (retrieved 19 October 2026)
  7. RoSPA — drowning prevention (retrieved 19 October 2026)
  8. Intex Ultra Frame pool manual, 2014, ground-cloth page (retrieved 19 October 2026)