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If you’re working with epoxy resin on wood, stone, or any other absorbent surface, adjusting your resin calculation is crucial. Porous substrates may absorb more product than you expect, potentially leading to uneven or patchy results if under-calculated.
Why Porosity Matters
Unlike non-absorbent substrates, porous materials such as timber, concrete, or pebble mixes can soak up a significant amount of epoxy during application. This means your standard volume calculation may fall short, leaving voids or dry areas. Even substrates that seem relatively dense can surprise you, especially in their raw or unfinished state.
How Much Extra Resin Should You Allow?
When calculating the amount of epoxy required for a project involving absorbent surfaces, it’s sensible to add approximately 10–15% more resin onto your base measurement. For large outdoor projects like those using the Flowstone Complete Permeable Floor Kit, this ensures thorough binding and coverage over uneven or open textures. For wooden tables or crafts, the same principle helps fill the material’s pores and achieve a smooth, sealed finish on the first try.
Practical Tips for Application
- Prime the surface wherever possible using a thin layer of resin before the main pour, to help seal pores.
- Monitor for signs of rapid soaking—patches that look ‘dry’ may need extra resin attention.
- Keep a small reserve of mixed resin handy to top up areas that absorb faster than expected.
When This Matters Most
Allowing extra resin is especially important for outdoor surfaces, rustic woods, and materials with clearly visible pores or cracks. Skipping this step risks compromising the durability and look of your finished project.
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Factoring in the extra resin required for absorbent or uneven surfaces is an essential step in any calculation. For more guidance on getting your measurements right, see our main guide on how much epoxy resin you need.