By February 2020 I was finally ready to start building. There was a fair amount of tedious preparation work such as removing rawl plugs, screws, nails and other fixings from the brickwork / woodwork. I was careful to mark where I need to back fill holes with chalk circles as they’re not that easy to see and failing to block them with mortar will affect sound insulation. I moved on to stripping out the old wiring and neon lighting and a temporary power supply was rigged up by an electrician.
I commissioned a steel flitch plate to reinforce the existing beam and the work was carried out by a local fabricator (to an excellent standard I might add – it was engineered to millimetre accuracy).
To build the flitch beam, I hired a local carpenter called Sean Butler (www.seanbutler.co.uk), who I already knew was great, very easy to work with and reliable. Because of the weight of the additional beam and steel plate, he brought his father Alan (also a very experienced carpenter and dry humourist – seeing the numerous chalk circles on the wall, he said he felt as though he was working at a “crime scene”) as well as an assistant. Before it could be fitted the supporting ‘pier’ needed attention because it wasn’t quite as tall as the one at the opposite end of the room. When the beam was originally installed it was leveled by packing the gap with blocks of wood(!!). So props were placed under the beam and the packing removed, meanwhile engineering blocks were cut to size and cemented in place. By the next day the mortar was firm enough to take the props away and the main structural reinforcement done! Next I set about sealing the outer leaf walls. To do this, I intended to fill the numerous drill holes in the brickwork and then apply two thick coats of masonry paint. Then, just as I was getting started, I encountered the first big setback. I had assumed that because the garage is built in to the earth at one side, this was a good thing. It has to be, doesn’t it? WRONG!!!!!! For the six months up to February, SE England had seen very high rainfall (for the previous 3 months it had been 155% of average and for February it was 250% of average). It seemed to rain non-stop, almost with no let up. Overnight on the 4th of March it was particularly bad, really knocking down to the point that the ground surrounding my house was completely saturated (there was standing water on the lawn). Inevitably, rain water found it’s way into the garage between the bottom of the wall facing the hill and the concrete floor. The chalk line in the photos indicates roughly where the ground level is on the outside of the wall.
I arranged for a drainage contractor to visit with a view to installing a French drain (named after it’s inventor rather than the country) and was waiting for the quote when the next big setback – covid-19, arrived. The resulting shut-down meant that it was impossible to buy materials for the project, although given the significance of world events, this didn’t actually seem very important at the time.
Fast forward to May 2020 and I had used the enforced delay to refine my design (largely as a way of occupying myself) and also gathered some very useful information about combating damp. I was in touch with a studio builder in Bristol called Tom, who built his studio on heavy clay soil next to a river which has been known to overflow. He recommended tanking the garage, whatever else I decided to do. So, as building materials became available again, this was the first job I tackled. I applied a coat of Construction Chemicals tanking slurry (as far as I can tell it’s a mixture of cement and glass fibres) up to one metre above ground level (said to be the limit of capillary rise in brick walls). Then added a wedge of mortar (or ‘fillet’) around the perimeter of the room where the slab meets the wall. When the mortar had hardened sufficiently, I painted on a second coat and left it to cure (the manufacturer recommends a full week). Not my tidiest work, but at least it will be hidden! Meanwhile I raised the two joists nearest the gables to make room for the inner leaf silencers, moved another one other to create more space between the rafters and pinned the others with M12 bolts. The raised joists will be reinforced (or ‘collared’) before any increased load is placed on them. Then I started to make a framework from softwood batten inside the gable timbers which is set in 30mm from the edge. I’m going to attach the Cement board and OSB3 cladding to this (after caulking it of course). I originally intended to pin the boards directly to the gable but doing it this way will increase the inter-leaf cavity by the thickness of the cladding.
A side-note that may be of interest to other project builders is that you can save a considerable amount of money on materials by bulk ordering. I found suppliers that beat trade prices by quite a large margin (£4 per sheet of OSB3, nearly £5 per sheet of MDF and over £6 per sheet of cement fibre board).
© John Steel 2020