Flexible Gap Fillers

Selleys Mortar Works


Selleys Mortar Works is a textured, ready to use weather resistant gap filler available in a range of colour to match your existing mortar. It’s mortar like texture allows easy repair of unsightly cracks and gaps in brickwork around the home.


  • Ready mixed mortar filler, so is quick and easy to apply with a caulking gun.
  • Has a mortar like texture for a textured finish and match to cement mortar and render.
  • Is more flexible than mortar which will help prevent more damage to the mortar.
  • Is weather and UV resistant with a UV stable formula to prevent colour deterioration.
  • Provides a more suitable finish on rendered walls than smooth fillers.
  • Contains a fungicide and algaecide to protect against unsightly mould and algae growth.
  • Has superior adhesion to a broad range of surfaces, making it easy to use.
  • Will not stain building materials.
  • Can be painted over with both water and oil based paints, after the surface has skinned. (Approximately 2 hours after application).
  • Is water based, so can be cleaned up with water easily.
  • Is sandable when dry for a rough or smooth finish.

Available Sizes

  • 440g Cartridge


  • Off White
  • Beige
  • Terracotta
  • Sandstone
  • Medium Grey
  • Charcoal

Where can this product be used?

102882.Brick wall illustCracks in gaps and brickwork
102816.Paving illustStationary gaps in pathways

  • Repairing cracks and gaps in brickwork and/or cement blocks where mortar has fallen out or eroded.
  • Stationary cracks in pathways.
  • Sealing gaps around windows or between brick wall and roof eaves.
  • Repairing stationary cracks in cement render.
  • Repairing penetration holes around pipe work, ducting, etc.
  • Sealing gaps where mortar has fallen out in ridge capping on tile roofs.
  • Not suitable for areas of continuous water immersion.
  • Not suitable as a substitute for mortar in construction as it does not have the structural properties of mortar.
  • Not suitable for moving cracks.
  • Do not use or store below 5oC.
  • Is not suitable for application at below 5oC.

What materials is this product suitable for?

  • Brick & Concrete
  • Plasterboard, particleboard & fibre cement sheeting
  • Ceramic tiles
  • Aluminium
  • Painted surfaces
  • Timber
  • Hardboards
  • Render
  • Many other building surfaces

How to use this product

  • Ensure the surface is clean, dry and free from dust, grease, flaking/powdery paint and old or crumbling caulk. If porous surfaces are greasy or dirty, we would recommend using SELLEYS LIQUID SUGAR SOAP. If the surface is non-porous eg glass or metal, firstly clean the surface with Mineral Turpetine and then again with Methylated Spirits. If there is old difficult to remove residue such as old paint, we recommend using paint stripper such as SELLEYS KWIK STRIP SMART. Ensure the surface is dry before applying the product.
  • Ensure you tape both sides of the gap before applying the product. This ensures a neat finish and makes it easier to clean up.
  • Cut the seal at the top of the cartridge and cut the nozzle at a 45° angle, to the size of the gap opening. Fit the nozzle to the top of the cartridge.
  • Insert the cartridge into a caulking gun such as SELLEYS LIGHT SPEED Caulking gun. We recommend SELLEYS LIGHT SPEED Caulking Gun, as its new innovative pressure release design reduces the mess which results from run on and stress on your hands, which is critical if you are doing a lot of gap filling.
  • Hold the caulking gun at a 45° angle. Press the nozzle opening against the joint, apply steady pressure to the caulking gun and extrude the flexible gap filler forcing the gap filler into the gap and move along the joint in one smooth action.
  • Press into the cracks and holes using a wet finger or for a professional finish use a paint scraper such as a 50mm ROTA COTA Soft Grip Scraper.
  • For larger holes or cracks, 2 applications may be necessary. Allow the first application to dry before applying the second. The product will harden in 24 hours, depending on the weather.
  • Clean up excess with a damp cloth immediately and clean hands and tools with water.
  • Do not use or store below 5°C.
  • Protect from rain until firmly skinned.
  • If you are filling a a crack in render, we recommend SELLEYS NO MORE GAPS Exterior Render Filler, which is a pre-mixed and textured rigid filler.

Handy tips

Tips for Repairing Mortar:

  • For the best results slightly dampen the surface prior to application.
  • When first applying product, extrude a small amount onto a piece of scrap material to ensure a smooth continuous flow of gap filler.
  • For use in fine lines eg cement render filler rub NO MORE GAPS Mortar Repair into the cracks or use NO MORE GAPS Render Filler.
  • If painting over the product, apply undercoat before applying a top coat for the best results.
  • Allow the surfaces to skin prior to painting, which is approximately 2 hours. Protect from rain until firmly skinned. Allow for longer skin and cure times in damp conditions.
  • Keep a pack of SELLEYS Sugar Soap Wipes handy to wipe up any spills and for cleaning. They are an easy and effective way to keep clean on the job.

Safety tips

  • Avoid eye contact and repeated or prolonged skin contact. Wash hands after use. Keep out of reach of children.
  • For advice, contact a Poisons Information Centre (AUS 131 126; NZ 0800 764 766) or a doctor.
  • For further detail on the safe use of this product, please refer to the Material Safety Data Sheet, which can be downloaded from this site.

Storage and re-use

  • Store in cool dry conditions, between 5°C and 25°C.
  • Product should be used within 6 months of opening.
  • After use keep the nozzle on the cartridge.
  • NO MORE GAPS is a water based acrylic sealant that dries by water evaporation. Sealing the nozzle with placsticene or Blu Tac then wrapping the nozzle in aluminium foil and sealing tightly with tape can prevent evaporation for longer storage.
  • Uncured NO MORE GAPS is sensitive to extremes of heat and cold. It should not be allowed to be frozen or heated during storage.