Epoxy Or Polyurethane Foam For Basement Crack Repairs?
A casual debate often will arise over the use of either epoxy or polyurethane foam for foundation crack repair. Both will fill the crack and stop water from entering through the crack. If stopping a leak is the only concern, then either product is fine to use.
The question remains, which one is better? That depends on the type of crack and conditions present at the time of the repair. The obvious difference between the 2 injection systems is epoxy will restore the structural integrity of the cracked wall by filling the crack with a high-strength adhesive that essentially ‘welds’ the cracked wall back together. Filling the crack with these high-strength epoxies eliminates the movement of the opening and closing of the crack in the wall that occurs during normal expansion and contraction of the soil during the seasonal cycles.
Polyurethane foam also fills the crack with a resin that expands in the presence of moisture and can be flexible enough to accommodate the same movement of the soil due to these freeze/thaw or wet dry cycles. Since polyurethane resin systems expand during the injection, less resin is required and can be much more economical to install especially in wider cracks or loose soil conditions. For a majority of foundation cracks the resin selection should be what the contractor is most comfortable using. Some cracks will have better repair results using one system over the other. For thin or hairline cracks, low viscosity epoxy resins will more often achieve better results because the epoxy will remain a liquid during the injection process allowing the resin the extra time that may be needed to fill tight hair line cracks when using low pressure cartridge type injection systems. For very wide cracks, the polyurethane expanding foam systems will fill the crack and do so with a fraction of the resin that would be required if epoxy was used. Wet or actively leaking cracks often will have better results being injected with polyurethane foam. There are epoxies that will work well in wet conditions as the epoxy will displace the water during the injection process, but extra care needs to be taken to “flush” out any resin that combines with the water. This is accomplished by continuing the injection of the epoxy coming out the next higher port and pushing out any resin that appears milky until clear resin flows out the port streak free.
There is a class of cracks that require expert review in terms of resin selection. Structural cracks due to movement and or settling of the home Cracks that are wider at the bottom or where the walls on either side of the crack appear deflected are often due to settling should be evaluated by a structural Engineer who can provide professional opinion on the best corrective action.
