Planning the electrical set out

Sometimes it just isn't enough to plan things out in your mind. You have to see it to figure out the problems. So it was for our electrical set out. We are using wall boxes to create a cavity behind the power points and light switches and conduits for the wiring. Hempcrete and wiring don't mix, so these measures keep them apart.

After Brendan the electrician installed nearly all the points in the extension, I noticed a troubling detail. The knock out in the wall box where the conduit enters the top was less than 10mm from the front face of the wall box. With the 25mm conduit on the inside of the frame and only 50mm of hempcrete cover on the inside, that would leave 25mm down to 7mm cover on the conduit. The risk of a crack along the line of the conduit looked too great.

Nothing for it but to relocate all the conduit to the outside of the frame and bring the wire into the back of the wall box through the noggin. Most of the positions worked out well, with a few tricky spots to work out with Brendan tomorrow.

All the conduits had been fitted with steel saddles. We could have painted them with Ormonoid, but it just seemed like hard work. Luckily I noticed plastic brackets on a trip to Bunnings, so I replaced them all as I relocated the conduits.



We nearly forgot the electric highlight windows. Hopefully we've got everything covered now. I don't want to think about gouging out to add an extra conduit after the hempcrete walls are built.

Preparing for Hempcrete

Look at the trusses, some were put up today. We had the weekend to do some painting before the trusses went up. Hempcrete is made up of hemp and lime. Lime and steel are not compatible. The lime will cause the steel to rust, even galvanised steel is not protected. What this means is we have to paint every nail plate, nail and every bolt with bituminous paint, that's a lot of painting. You can see below the black paint on the trusses.

Another thing we have to do to prepare for the hempcrete was to tilt all the noggins on the frame. We had to cut through one of the nails on each side so that they could be tilted at around 30°. If the noggins remained horizontal it would be difficult to infill hempcrete under the noggin, whereas when they are angled the hempcrete should fill more easily. There is quite a lot of preparation!

The noggins have been tilted and renailed

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Tilly helping to paint the nail plates