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Dot and dab fixings for blockwork behind the plasterboard

Updated: 22 October 2026

You tap an internal wall in a UK new-build and it sounds hollow. The plasterboard is only the skin. Dabs of adhesive hold it off the block, and that gap is why a short plug spins or pulls gypsum out of the face. Dot and dab fixings for blockwork have to cross the cavity and bite the masonry, often aerated block rather than dense brick. The ten amazon.co.uk cards, with October 2026 prices in GBP, are on the [aircrete fixings comparison](/hub/screws-and-accessories/aircrete-fixings). This is not a pull-out test. A qualifying purchase through our links can earn a commission at no extra cost to you.

You tap an internal wall in a UK new-build and it sounds hollow. The plasterboard is only the skin. Dabs of adhesive hold it off the block, and that gap is why a short plug spins or pulls gypsum out of the face.

Our top picks

Corefix Corefix 100 mm (24)

Best overall

Corefix Corefix 100 mm (24)
9.0/10about £21.00
View offer
Corefix Corefix 100 mm (4)

Best value

Corefix Corefix 100 mm (4)
8.6/10about £6.30
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Rigifix Rigifix M8 (4)

Alternative

Rigifix Rigifix M8 (4)
7.3/10about £8.99
View offer
On this page
  1. 1.How to tell you are in a dabbed wall
  2. 2.Which bridge actually reaches the block
  3. 3.How to split a television across the holes
  4. 4.What goes wrong in the hole

How to tell you are in a dabbed wall

A dabbed wall is plasterboard bonded to masonry in blobs, not screwed to timber studs. Knock it and it booms. A pilot hole shows gypsum, then a short gap, then block. On many newer houses that block is Thermalite, Celcon or similar aerated concrete. Confirm it on the wall in front of you. Dry lining is common, and that is a rule of thumb, not a survey. A picture hook can live in the gypsum. A television, a radiator or kitchen units have to reach the block. Soft, sandy dust means aerated. Hard grey spoil means dense masonry, on the aircrete fixings versus standard wall plugs page. Look for cables and pipes before a row of holes. A boiler or a heavy stone surround is when you call a professional.

Which bridge actually reaches the block

Three families in this set cross a dab cavity. Corefix is a UK-made steel-core screw. Fischer DDF is a two-component fixing with matched screws. Rigifix is an M8 sleeve and screw. Fischer GB Green, £8.49 for 20 hammer-in spirals, is for bare aerated block you can see. It does not bridge plasterboard. The Corefix 100 mm 24-box is £21.00, with 4.7 from 1,437 ratings. A short hole wastes a plug, and there is no drill bit. The four-pack is £6.30, and dust crushes the plug. The six-pack at £9.49 includes a 10 mm bit and excludes a cantilever bracket. Rigifix needs a 16 mm hole and hand torque. Its 280 kg line is maximum shear on the listing. DDF is 50 pieces without a kilogram you can divide.
Corefix Corefix 100 mm (24)

Testsieger

Corefix Corefix 100 mm (24)
9.0/10about £21.00
View offer

How to split a television across the holes

Divide the set and the bracket by the holes that will carry them. A 15 kg television on four fixings is under 4 kg a point. A 12 kg radiator on four is 3 kg a point. Both sit under a 55 kg highlight, and that sum still does not allow a cantilever arm. Corefix listings exclude those brackets. The 100 kg bullet is four points together. The 150 kg line is six fixings. Two holes do not inherit the four-fixing total. Rigifix's 280 kg shear is not a number to add to 55 kg. None of this is a pull-out test. If the bracket stands off the wall, change the mount. The best aircrete fixings page sorts the cards once you know the wall.

What goes wrong in the hole

Drill, clear the dust, then drive. Dust is why a Corefix core fails to seat. Go through the board, across the gap, and into block. If the screw tightens in the cavity, you are only holding gypsum. A 10 mm bit is in the television six-pack only. Rigifix wants 16 mm, so that bit does not transfer. A GB spiral is the wrong family on this wall. Load the finished bracket flush, not with your weight on an arm.

Common questions

Are dot-and-dab fixings suitable when the block behind the board is aerated?
Yes, when the fixing bridges into that block rather than sitting in the plasterboard. Corefix bullets name lightweight and aerated block as well as dot and dab. Rigifix bullets name Thermalite. Fischer DDF is sold for a plasterboard cavity over masonry. A hammer-in GB spiral is listed for bare aerated concrete, not for this gap. Confirm there is block behind the board. Studs, or board over insulation, are a different wall.
How many fixings do I need for a television?
Divide the set and bracket by the holes you will use, and keep each share inside the listing's per-fixing claim. A 15 kg screen on four points is under 4 kg each, which is inside a 55 kg highlight and still the wrong layout if the bracket is a cantilever arm. Corefix tells you not to use that arm. The 150 kg line is six fixings together. Four holes do not inherit it.
Should I buy GB Green or Corefix for an internal dabbed wall?
Buy Corefix, or another bridge such as Rigifix or fischer DDF. GB Green is a hammer-in spiral for bare porous block. On plasterboard it does not cross the adhesive gap, so the £8.49 box is the wrong family even though the title says aircrete. Use the green spiral where you can see the block, such as a thermobloc garage. Use the steel-core screw where the wall sounds hollow.
Do I need a 10 mm drill bit?
You do for the Corefix cards that specify a 10 mm hole, unless you buy the television six-pack, which includes a 10 mm masonry bit at £9.49. The 24-packs do not include a bit. The 120 mm box also wants 120 mm of depth, so a short bit is not close enough. Rigifix is a 16 mm hole. Match the packet, then clear the dust before you drive the screw.
Can I use these on a cantilever television arm?
Not the Corefix packs. Those listings say a cantilever bracket is not recommended, and the review notes repeat it. A flush mount on plasterboard over block is the job they describe. A long arm changes the pull on the top fixings even when the weight, divided by four, looks small beside 55 kg. Rigifix does not give a cantilever clearance in this file either. Its 280 kg line is maximum shear, not permission for an arm.

Related pages

How to install aircrete fixings

Aircrete fixings

Best aircrete fixings for garages, dabbed walls and TVs

Aircrete fixings buying guide: match the wall before the box

Aircrete fixings vs standard wall plugs after a spin-out

Sources

Listing pages named in the research digest, last checked on 22 October 2026. Prices, stars and review counts are the stored amazon.co.uk figures for October 2026. Kilogram lines are seller wording, not a pull-out test.

  1. fischer GB Green aircrete anchor, amazon.co.uk B011O6L016 (retrieved 22 October 2026)
  2. fischer FPX aircrete metal anchor, amazon.co.uk B00BTFYC36 (retrieved 22 October 2026)
  3. Corefix dot-and-dab fixings, amazon.co.uk B072JYXJL6 (retrieved 22 October 2026)
  4. Rigifix M8 anchor fixings, amazon.co.uk B00D98LHLG (retrieved 22 October 2026)
  5. fischer DDF dot and dab 50 pack, amazon.co.uk B0DVCCSKHK (retrieved 22 October 2026)
  6. fischer SXRL frame fixing range, amazon.co.uk B077YKRBF2 (retrieved 22 October 2026)