ᐅ Reinforcement mortar for exterior insulation systems at current temperatures

Hello everyone,

In two weeks, our prefabricated house will be placed on top of our prefabricated basement, and this Saturday we want to insulate the half of the basement that is not in contact with the ground. The basement is downhill, and the ground-contacting side has already been insulated.
Now I am wondering how to best install the perimeter insulation boards in the lowest row as well as the remaining insulation boards.
To even out the irregularities of the bitumen membranes (used to seal the prefabricated joints), I was thinking of using reinforcing adhesive or mortar. Unfortunately, these products can only be applied at temperatures above +5°C (41°F). I found StoLevell FT from STO, which can be used from +1°C (34°F), but it is quite expensive at €40/25 kg.

Do you have any suggestions on how to install the insulation boards at temperatures between +1 and +9°C (34 and 48°F)?

The boards need to be in place by calendar week 3, 2019, as the screed will be installed then. Since temperatures are more likely to drop than rise, I would prefer to complete this work beforehand.

Oh, and one more detail: this basement is purely a utility basement.

Thanks in advance!

You are left with only the compound approved for +1°C (34°F), or you have exactly the time when there are no cold nights. Here (400m above sea level) it currently doesn’t get below 5°C (41°F) at night. I would still use the standard material in that case. At +1°C (34°F) it’s tricky because it depends on how many hours after application you reach +1°C (34°F) and what the temperature was at the time of application.

I have now found an insulation adhesive that works down to -5°C (23°F). It also evens out slight irregularities. This should work, right?

It usually works out somehow (no guarantee for this statement!). I would generally use materials from a single supplier and stick to the manufacturer’s system.

Please also ensure that the adhesive is suitable for bituminous substrates. If the surface irregularities are too large, the substrate should first be leveled before the boards are glued. At 5°C (41°F) substrate, material, and drying temperature, I would still use "standard" materials.