Cold Applied Liquid Waterproofing Membrane for Basement Foundation
Looking at finalizing the specifications for my basement foundation. Have looked at many of the details and articles here and elsewhere are will add capillary break between footing and foundation along with adequate drainage pipes, crushed stone, fabric at the foundation (likely outside and inside) with sump system and pumps. Continuous insulation inside the basement.
As for waterproofing, I want to specify a cold applied liquid waterproofing membrane before a dimple drainage mat. I’ve seen Tremco Tuff-N-Dri mentioned here a few times as one having a tested hydrostatic head resistance. The upgraded version Tuff-N-Dri XTS has been tested to 12 ft of hydrostatic head, which would be the one I would use.
I then came across WR Meadows Mel-Rol LM in my research. They specify 48 psi which is 110 ft of hydrostatic head. Great! I thought. Then I started think, how can a similar asphalt based polymer modified liquid applied membrane have ten times the hydrostatic head resistance compared to the Tremco product? Is this too good to be true? The test for Tremco is ASTM D- 5385 which is the proper test. Mel-Rol cites ASTM D751 which is the test for a water resistant fabric. Mel-Rol also claims zero VOC which I find quite odd as the SDS lists asphalt and oil base stock as the main components.
I guess my questions are, has anyone used Mel-ROL LM before and is their claim of hydrostatic head resistance almost 10X of Tremco Tuff-N-Dri XTS too good to be true?
The product sheets and specs are attached.
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Replies
I would guess that what you are trying to achieve is damp proofing, not waterproofing. Damp proofing is blocking the transfer of water from the ground to your building, and is the standard for most residential construction.I t looks like the assembly you plan on using is well thought out and should be sufficient, but the application of a waterproofing membrane may be unnecessary. The drainage piping, crushed stones (no fines) and dimple mat will solve any water ingress by capillary action, and you could use a damp proofing material instead of a waterproofing material.
Waterproofing is used when your foundation is truly within the water table, and will be subject to substantial hydro-static pressure. The materials and systems start to look a lot more like roofs than typical walls.
An asphalt based damp proofing spray before the dimple mat is common practice here. I'm trying to achieve an extra level of water proofing as an insurance without resorting to the extra cost and complexity of a more robust peel and stick solution.
Check this system: https://www.dorken.com/en/our-products/products/residential/delta-ms.php