What hempcrete actually does to a Gauteng winter energy bill

Hempcrete is not a structural material and it is not trying to be. Its value sits in what it does to the envelope: it buffers heat and moisture at the same time, which is exactly the combination a dry Highveld winter punishes.

Over 14 weeks we logged internal temperature and relative humidity in two 12m² test frames on our Kempton Park site. The hempcrete frame held a narrower internal temperature band overnight and never dropped below 41% relative humidity, while the plastered brick frame swung wider on both.

The practical read for builders: hempcrete lets you meet an envelope performance target in a single layer, which cuts a trade off the programme. The trade-off is drying time, and that has to be planned into the schedule rather than discovered on site.