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Paving joint mortar for a measured patio gap

Updated: October 2026

You have a tape on a patio joint and three products that all sound like paving joint mortar. A cement bag, a brush-in tub and a thin-tile grout fill different gaps. Start with the width and depth you can see, then the slab and the base, and only then the pack. The [paving joint mortar comparison](/hub/flooring-tools-and-accessories/paving-joint-mortar) holds the cards and prices. One listing per job is on [best paving joint mortar](/hub/flooring-tools-and-accessories/paving-joint-mortar/sub/paving-joint-mortar-best). Thin slabs sit on [porcelain paving joint mortar](/hub/flooring-tools-and-accessories/paving-joint-mortar/sub/paving-joint-mortar-porcelain). The damp mix versus a permeable tub is [jointing compound vs sand and cement](/hub/flooring-tools-and-accessories/paving-joint-mortar/sub/paving-joint-mortar-vs-sand-and-cement).

You have a tape on a patio joint and three products that all sound like paving joint mortar. A cement bag, a brush-in tub and a thin-tile grout fill different gaps.

Our top picks

Bostik Bostik Cementone mortar, 10 kg

Best overall

Bostik Bostik Cementone mortar, 10 kg
9.0/10about £14.99
View offer
Bostik Bostik All Weather jointing compound, 15 kg

Alternative

Bostik Bostik All Weather jointing compound, 15 kg
8.8/10about £39.35
View offer
Dansand Dansand Kerama patio grout, 15 kg

Alternative

Dansand Dansand Kerama patio grout, 15 kg
0.0/10about £39.99
View offer
On this page
  1. 1.Measure the joint before you choose a tub
  2. 2.Mix-it mortar, brush-in compound, or a thin-tile grout
  3. 3.What the kept listings actually state
  4. 4.Drainage, weeds and the front garden

Measure the joint before you choose a tub

Width and depth decide the family before a tub looks convenient. A gap around 10 mm on a thick concrete flag is a different job from a 5 mm joint and from a butt joint near 2 mm. A compound that needs 25 mm of joint cannot sit in a shallow groove. Measure several joints, not the neat one by the door. A butt joint near 2 mm sits outside this set. Bostik's sheet starts at 5 mm, Dansand Kerama's maker page at 3 mm, and Joint-it's maker page at 3 mm. A grout that states 2 mm is not in this comparison.

Mix-it mortar, brush-in compound, or a thin-tile grout

A damp sand-and-cement point is the usual branch for stable concrete flags on a full bed. A brush-in compound replaces the mix only when the joint is wide and deep enough and the base can drain. Bostik's UK sheet states 5–30 mm wide and at least 25 mm deep, and it excludes a base that stays wet. The amazon.co.uk bullets still name driveways. Treat the sheet as the limit. Thin porcelain, often 20–30 mm, is a third branch. Kerama is the listing that states that thickness.
Bostik Bostik Cementone mortar, 10 kg

Testsieger

Bostik Bostik Cementone mortar, 10 kg
9.0/10about £14.99
View offer

What the kept listings actually state

Laeto Easy Mix is pre-blended, and the bullets name pointing and bedding, with no joint width. Joint-it Simple has no millimetres on the listing, so do not treat its American coverage lines as UK figures. Stars only break a tie inside one branch.

Drainage, weeds and the front garden

A permeable joint and a rigid cement joint move water differently. The Bostik compound needs a bed that can take water away. A cement point is the low-permeability option, so the fall of the slabs has to do that work. Neither is a promise that weeds stay out for the life of the patio. Northern Ireland is not the England, Scotland or Wales rule. Buy the smallest pack you can finish before it sets in the bucket.

Common questions

What should you measure before you buy paving joint mortar?
Measure width and depth in several places, plus slab thickness and whether the flags sit on a draining base or a solid bed. A 10 mm joint on a thick concrete flag is not the same buy as a 3 mm joint on 20 mm porcelain. Write down the narrowest gap, because the product's minimum width fails first. If a corner rocks, repair the bed before you buy filler.
When is a damp sand-and-cement point the right branch?
Use it on stable concrete flags when you want a rigid joint and you can sponge the face straight away. Marshalls describes about 1:4 for many flags around 10 mm wide and at least about 22 mm thick, on a full bed. Skip it if you need a stated permeable joint of 5–30 mm, or if the slabs are thin porcelain. A 1:6 Home Pack is sand and cement, and it is leaner than that 1:4.
When does a brush-in compound replace that mix?
It replaces the mix when the joint is inside the tub's width and depth and the base can drain. For Bostik All Weather, the UK sheet says 5–30 mm wide and at least 25 mm deep, curing in air, and not on a wet base. It does not replace mortar on a 2 mm butt joint, on traditional block paving, or on a driveway if you follow that sheet. The amazon bullets that mention driveways disagree with the sheet.
Why is a 1:6 Home Pack not the same as a pre-blended tub?
Both Home Packs say mix 1 part cement to 6 parts sand, and reviews say the parts arrived as separate bags. Cementone and Laeto are pre-blended powders you wet. A 1:6 ratio is also weaker than the damp 1:4 Marshalls describes, and some reviews found a joint soft enough to mark. The cheaper bag is not the same joint as the pre-mixed tub.
Can a cartridge replace a bag?
The SX 300 ml tube is for small pointing in the dry above 5°C, and the gun is not in the box. Reviewers describe a stiff paste and a few slabs of coverage, not a patio. It states no joint width and it bonds poorly on a damp surface. Use one tube for a short repair. Use a bag or a tub when the joints run the length of the path.
Does a permeable joint let you skip the front-garden rule?
No. In England, more than 5 m² of hard surface between the house and the highway must be porous or drain within the garden. The joint is not that whole surface. Scotland's Class 3C note has no 5 m² exception, and Wales treats up to 5 m² of repair differently. A permeable compound can be part of a draining build. It is not consent.
Which listing has no UK star line at all?
Dansand Kerama, 15 kg at £39.99, has no Customer Reviews line on the captured amazon.co.uk page. You cannot set it beside Cementone's 5,459 reviews. Judge it on the stated use: ceramic and porcelain 20–30 mm thick, joints up to 10 mm on the listing, with the maker adding a 3 mm floor, 20 mm depth and an unbound base. Missing stars are a reason to read the porcelain page.

Related pages

How to point patio slabs

Paving joint mortar

Best paving joint mortar for the job in front of you

Porcelain paving joint mortar for thin 20–30 mm slabs

Jointing compound vs sand and cement on a single patio

Sources

Public sources used for this comparison, with the amazon.co.uk listings read on 20 October 2026.

  1. Bostik UK TDS02249, All Weather jointing compound (retrieved 20 October 2026)
  2. Joint-it Simple (retrieved 20 October 2026)
  3. Dansand Kerama (retrieved 20 October 2026)
  4. Marshalls concrete paving installation guidelines (retrieved 20 October 2026)
  5. England: permitted development technical guidance (retrieved 20 October 2026)
  6. BSI on BS 7533-101 (retrieved 20 October 2026)
  7. HSE: cement (retrieved 20 October 2026)
  8. HSE: chasing concrete and raking mortar (retrieved 20 October 2026)