Building Blox: Week 12 – Roof timber structure kicks off

What we did:

• Roof timber structure started,
• Finalised roof window positions.

This week the carpenters, or ‘chippies’ as they’re called in the trade arrived on site and began putting together the roof structure. The main guy, a seasoned pro, took me through how the structure will be built and we discussed the many roof lights.

Given the site location and orientation, there isn’t much scope for regular windows to provide natural light, so I’ve introduced a ridiculous 6 roof lights into each house. Frames for each of these need to be integrated into the roof structure, doubling and tripling up rafters for adequate support.

Back to GCSE maths

When installing roof lights, these are usually set in relation to the room dimensions, squaring up against the internal partitions. In this case, as there are no internal walls yet, we had to estimate where these should be and I use some GCSE trigonometry to figure out the positions. Armed with the SOH CAH TOA formulae, we could measure out the roof light positions onsite and set the rafter positions.

And if you’re wondering, the position of these are carefully measured out using a weighted piece of string suspended from the roof to form a plumb straight vertical line. You can’t get more accurate than when you use gravity! Similarly, a friend was recently telling me how he still uses other ‘medieval’ methods in his building projects, like using water displacement to set horizontal levels.

Building to a higher standard

Whilst the roof structure was being made up, inside we started laying insulation for the ground floor, which limits heat exchange from below the beam and block floor. As with the insulation which has gone in within the external wall, a particular specification and size must be used in order to meet the environmental standards within Building Regulations. To meet a higher standard I’ve designed, in most instances we’ll be using higher specification materials, so the houses go over and beyond the normal standards. As a result heat loss will be reduced and energy bills lower.

First little dispute...

I guess it was bound to happen sometime, and this week my contractors and I had a dispute about the extent of their work excavating a trench to the main road in order to lay pipework for the utilities. In short, the contractors felt the tender document wasn’t entirely clear on the work and so want to be paid for additional work. What we did agree on is that we must solve this ASAP and amicably! There’s still long way to go, so I’m sure unfortunately this won’t be the last…

Next week the chippies were to carry on building out the roof structure and we looked to get the ground floor finished with yet another concrete truck onsite!