It's bad enough when things go slowly, it's even worse when they go backwards.

I went out to site with the intention to prepare for laying the "atrium" area - ie between the front and back bedrooms and all the wet areas.

I had hoped to knock this over in an hour and then move on to a whole lot of fiddly jobs I have been avoiding.

The first job was to reconfigure one floor joist so that the atrium section of floor would end up with a neat join line just under the set of back bedroom doors.

This actually worked out very well - I just had to continue an existing line by relocating a 2 metre joist. It needed some additional notching for this to work but apart from that it was quite straight forward.

The problem arose when I took a closer look at the loft plan and realised that it required two 820 doors to be installed for the front bedrooms and back bedrooms in a space of 1800 mm.

This is the width of the hallway at the street level and I had assumed that the atrium walls would be built directly over the these stud frames.

When I applied my scale ruler to the plans I could see that each atrium wall in the loft was actually 1 mm on the scaled plan further out to the perimeter - ie 100 mm wider on each wall.

This meant that atrium is meant to be 2000 mm wide (sitting over joists that are 2200 wide so that allowing for 100 mm for the wall width on either side the clear space is 2000 mm).

It's not too late to sort this out - I just have to replace 10 joists that are currently 2000 mm with joists that are 2200 mm in order for these loft frames to be very slightly cantilevered out from the hallway walls.

I remember that installing these joists originally was very fiddly work so I am not looking forward to replacing them.

I phoned Tony M and worked out that it is possible to just fit the two doors into 1800 mm.

However, this reduces the atrium width by 200 mm and I know I will be kicking myself in a few years time when we carry a bed base up the stairs and then can't manoeuvre it in to a bedroom because of the reduced width.

When Jim and Sandy visited I discussed my problem with them and they suggested a way to create the 2000 mm width without needing to replace the joists.

However, this involved transferring some of the roof load on to the set down floors in the wet areas and could increase the risk of tiles or screed cracking.

Also it would have involved the use of point loads and lintels in the affected stud frames - so possibly creating more work that it solved.

I fetched out 10 purlins, washed them down with a pressure cleaner and loaded them on to my utility.

During the week I will cut them to length and touch up any white oxide areas.