Having done the ripping down and strengthening up of the building by putting in metal beams, we arrived at the stage of taking off the main roof.
Lots happens at once during an eco-renovation
The builders took all the tiles off the main roof, and stored them in the front garden as they will go back onto the new roof. Whilst this was going on there was another team putting in the new joists for the attic bedroom floor, the old ones having been totally removed. You can see in this photo that there is a bit of plastic sheeting poking out over the tops of the walls. This is the start of the airtight layer that will eventually line the whole of the inside of the house. It will be continuous, with the sheets joined by a special tape that makes it completely airtight so no cold can get inside.
Working out what straight is!
One issue that came up was the front wall of the cottage, which isn’t straight at all. Sandy, the architect, had a meeting with the builder to decide where straight is, as far as putting the roof back on goes. They looked at the plan in the photo below and decided where straight would be. This was quite a complicated task because they had to follow the roofline of the neighbouring house and to take into account the line of the back wall. At one point, it looked as if the pitch of the roof might have to be at a different angle at the back from at the front. In the end, they were able to make the straight line though back wall parallel to the straight line at the front and so the pitch is even.
Sandy took a line which is going to be the straight roof line, and where the wall bends in, the eaves of the house will overhang a bit more at one side. There has to be something covering the insulation etc when you look up at the underneath of the overhang, every detail from every angle has to be thought of. But it’s all a bit wonky, it’s an old house after all!
Luckily the back wall is fairly straight. Having said that, it might be straight horizontally but it is uneven vertically, which caused some challenges you can read about in The Main Start of the Eco Build – Unbuilding and Ripping Down.
An old man who used to live in the village told me that he could remember when the house used to be one storey, and the people who owned it took off the original thatched roof and made the walls higher. The walls of the original cottage have two layers – an inner and outer shell. When the new wall was added, it was only one layer thick, and surprisingly it was the inner layer they extended! This creates a shelf on the outside where the two walls meet. The shelf was of mortar and open to the elements. Because mortar is porous, water could seep in.
Between the layers, the original builders put rubble and waste building material, some as fine as dust. Over the years, this settled, but with the porous shelf this settling increased, since rainwater soaked through and washed it down. This meant much of the wall had no insulation and it was no wonder I was so cold during winter. It also meant that when the Society for the Protection of Ancient Buildings (SPAB) came to check the cottage for damp, they found it – but in an unusual place. It was very damp just below the shelf, so water had seeped in. The dampest place on an old wall is normally close to the ground where water gathers, and this can soak up the wall.
To protect the cottage from further seepage, the simplest solution is to make the shelf watertight, most likely by fully covering it with a sheet of lead. This lead covering is a job for later on in the build, and meanwhile the builders took the old roof off, saved the tiles and started work on creating the new roof. You can read all about that in my next post.
CotswoldEcoBuild 