It’s only just dawned on me that I haven’t updated the blog with progress on the garage. So, a bit (lot) belatedly here it is…
The concrete slab was poured and levelled in no time at all. We put a few ducts in the slab to bring water, electric and internet up but most ended up being too far from the walls to be much use (no point in having the electric cable 200mm away from the wall). The only one that we’ll use is for bringing the internet cables up and the others will be blocked off. Electric and water will now just come in through the walls.
We have two wires for internet in the garage. One is to connect a PoE CCTV camera and the other is to get wifi in there. There is a signal from the house but it’s pretty weak.
The structure is single-skin blockwork with a flat roof. I was originally going to make it well-insulated (slab/walls/roof) as I do quite like to tinker in the garage but I couldn’t justify the increase in cost and I could better spend the money in other areas at the moment. I may well insulate the roof area and walls at a later date but it’s not on my list of priorities any more.
The walls themselves went up really quickly and in just a couple of days you can see what a great space it will be. The garage is about 6.7m in each direction, so not small!
We went with a flat roof on the garage for a couple of reasons: we felt it was more in-keeping with the design of the house; and as the garage is quite close to the front boundary and footpath, we felt that having a flat roof would lessen the impact it would have on the road. We’re good like that 🙂 Anyway, Planning were happy with that so that’s what we’ve got!
The roof trusses specified by the architect were solid timber but these posed a few issues. Namely that to get the span we would need quite large cross-section which in turn makes them incredibly heavy to lift – they’re also hard to come by. In addition, solid beams make it more difficult to pass services around the roof space. The obvious solution is to use the metal web joists that we have used successfully in the rest of the build.
Obviously a flat roof needs to drain, but how? A very good question!
To get the fall from front to back we nailed firrings – long lengths of timber that a gradually tapered. We went for a fall of about 1:60, which is more than needed. Normally these would be fixed straight to the top of each joist but we wanted the fall front to back, not side to side so the firrings are perpendicular to the joists, not parallel with them. The roof was then covered with 2440x1220mm boards of 18mm thick OSB3.
My dad and I did this (the firrings and OSB) over 3 short days but it could easily be done in 1 if needed.
The next issue to overcome was what to waterproof the roof with. I didn’t want to use the same stuff that we put above the kitchen as it is just too messy. After looking at all the options I decided we were going to use a rubber membrane (EPDM). Some people love it, others hate it, but at the end of the day this was just going on a garage so if there was a problem with it then it’s not the end of the world.
Next question – who to fit it? I asked around and eventually got someone to quote for the work, which came in at £2100! He said it would only take a day so I looked up the cost of the materials – about £700. So £1400 labour for 1 day. I don’t pay anyone £1400 for a day’s work and decided I would do it myself. I mean, how hard can it be? As always, ‘not very’.
The single-piece rubber membrane was supplied with the adhesives and a few other bits and pieces. So armed with a few YouTube videos we set to work. Problem number 1 was how to get it on the roof as it was so heavy – about 120kg I would guess. A small hired lift got it up in no time, although it did cost nearly £100 for 10 minutes of use!
The process of glueing the rubber to the roof is very simple. We did end up with a few creases but partly this was due to the difficulty in trying to manouevre the rubber. In the end it’s pretty good (I’m happy with it) although if I did it again I would tackle the job slightly differently. However, we did save over £1000. Which is nice.
The roof has now been in place for over a month and despite some incredibly heavy wind and rain there are no leaks, so I suppose that vindicates my decision to do it ourselves. This is despite the fact that we are yet to fit the copings that will give more edge protection – these will go on once the rendering is complete.
A door has also been fitted. This is quite a big deal as it means that lots of stuff we were keeping in the house can now be secured outside. The door itself is from Garador, part of the Hoermann company and is an insulated sectional door, electrically operated.