Earl’s MulTflex® Exterior Flexible Filler is a unique, single-pack, ready-to-use flexible filler and adhesive formulated for lasting repairs on timber and masonry. It delivers a durable, non-shrinking, non-sinking finish that won’t crack with vibration and won’t fall out, making it ideal for exterior maintenance where movement and weather can defeat ordinary fillers. Paintable when dry and formulated with no volatile organic compounds (No VOCs), it’s a dependable, low-odour solution for professional results at home or on site. Proudly 100% Australian made and owned.
Why you’ll love it
Exterior-grade flexibility: absorbs movement and vibration without cracking.
Non-shrink & non-sink: holds profile and edge detail after cure.
Won’t fall out: engineered adhesion for long-term durability.
Ready to use: straight from the tub — no mixing, no mess, no waste.
Paintable: achieves a seamless, colour-matched finish once dry.
No VOCs: low odour, solvent-free formula.
Interior / Exterior: versatile enough for both.
Proudly Australian: made and owned in Australia.
Where it works
Use Earl’s MulTflex® to repair and rebuild on a wide range of common building substrates:
Timber: decks, window frames, trims, fascia, general carpentry repairs.
Masonry: brick, block, render and patching mortar-like defects.
Plasterboard: exterior-exposed linings under cover and general patching.
Metals & gutters: non-structural filling and profiling (clean, sound, free of rust).
Around pipes & penetrations: neat, gap-free finishing before painting.
Glass & surrounds: edge repairs and feathering prior to topcoating.
Ideal projects
Rebuilding weathered or rotten timber edges before repainting.
Filling cracks and surface imperfections in rendered walls.
Profiling and feathering joints and transitions for a paint-ready finish.
General exterior maintenance where a flexible, paintable filler is essential.
Directions
Surface Preparation
Remove loose or flaking material, dirt, dust, oil, grease and chalky paint. Substrates must be sound.
Ensure surfaces are dry and free from visible moisture. Treat rust and stabilize friable areas as required.
For best mechanical key, lightly abrade glossy surfaces and remove dust.
Application
Open the tub and use directly. If the surface of the product begins to dry, add a few drops of water and re-mix gently. Keep the container tightly sealed when not in use.
Apply with a filling knife or trowel, pressing firmly to ensure full contact with the substrate.
Build up in thin layers for deep repairs, allowing each layer to firm before adding the next.
For a satin-smooth finish, tool the final pass with a wet knife or brush to reduce post-work finishing.
Finishing & Painting
Allow to dry fully. Dry time varies with film thickness, temperature and humidity.
Once dry, apply a suitable primer/undercoat if required by your paint system, then topcoat.
Use quality exterior paints for weather-exposed areas.
Clean-Up & Storage
Clean tools and splashes with water while wet.
Reseal immediately after use to minimise skinning and reduce waste.
Store upright with lid sealed. Do not allow contents to dry out.
Good to know
Formulation is unaffected by normal temperature swings and resists cracking with vibration.
Designed for exterior flexibility yet also suitable for interior touch-ups.
For best results on deep voids, fill in multiple light applications rather than one heavy pass.
Specifications
Brand
Earl’s
Product
MulTflex® Exterior Flexible Filler
Type
Single-pack, ready-to-use flexible filler & adhesive
Use
Interior / Exterior
Paintable
Yes, once fully dry
VOC Content
No VOCs (as supplied)
Shrink / Sink
Non-shrinking, non-sinking
Flexibility
Resists cracking with vibration and movement
Clean-Up
Water (while wet)
Substrates
Timber, masonry, render, plasterboard, metals, gutters, around pipes, glass
Finish
Satin-smooth when tooled with a wet knife or brush
Packaging
Ready-to-use tub
Country of Origin
100% Australian made & owned
Limitations
Do not apply to unsound, dusty or actively corroding surfaces without proper preparation.
Dry and cure times depend on depth and conditions; confirm dryness before painting.
Not intended for structural repairs.
Pro Tips
Feather edges wide for invisible paint blending on weathered timber and render.
Keep a small cup of clean water nearby to maintain a smooth final pass.
Deep cavities: bridge with successive thin layers for the most stable result.
Read more less