Number 41 takes shape

Andy and Sarah Ball have made great strides on their sustainable Derby build since they last reported in Selfbuilder + Homemaker. Sarah updates on the recent progress.

When you left Number 41 the last time round, the one tonne steel reinforcement had just been lowered into position to hold up the first floor of the master bedroom at the back of the house and to create the lintel for the oversized glass doors on the ground floor.

Three months later, and Andy and I are pleased to report that the house is almost watertight. The superstructure is complete, the glazing is ordered and due in the next 10 days, the roof is on, and the rendering booked in.

We’re continuing with our theme of building an energy efficient home, but using low-cost, traditional construction methods. The walls, now completed, are double skin breeze block with an overall span of 400 mm. Packed with insulation and drylined, they have a U-value 0.12 W/m2K, which is pretty good. Because there’s so much glass – to create a light and airy living space – we are going triple glazed. This is designed to keep the temperature as even as possible.

On the south facing side there’s a large triple track aluminium sliding door, spanning almost eight metres. Split into three equal sections, this also determines the layout of the open plan room by dividing it into the living, dining and kitchen areas. It’s one of the most important decisions we’ve made, especially as it’s on show both inside and out. The criteria for the decision was that it had to be able to divide into three, so we could open two thirds of the door. When shut, we wanted the thinnest frames possible, so the view out isn’t obstructed.

We have plumped for AluK’s Infinium glazing, manufactured by AluFoldDirect, with black frames on the inside and out, it will give the illusion that they almost disappear. We’re getting all the aluminium windows from them as well. The design at the front includes two very tall, thin windows, we have switched these to a curtain walling system to maintain this striking design feature. What’s really impressive is that now the roof is on and ceilings are in place, we can see that even on the north facing side how much natural light will come in through the floor to ceiling glazing.

The weight of the glass is a big concern during the installation. Because it’s a very tight site, there’s no room for cranes, so most of the glass will have to be lifted by hand. We have been calculating the weights of the triple glazed units and working out how many extra bodies we will need on site when the glass gets delivered! We won’t be able to do this with the very largest units, so we are looking at a glass lifting robot for the side glazing and rear doors.

The roof is fitted. It’s a flat roof surrounded by a tall parapet, and it’s big. The total area is almost 120 m2. After much discussion we went for a ‘cut to falls’ insulation to give us the best combination of insulation and drainage. The insulation fits together like a jigsaw, with all the pieces numbered, creating the perfect run off for rain. The waterproofing layer is PVC single ply and is welded together. The roofing team from Proactive Flat Roofing picked some excellent weather to start the job, but the following day it was howling a gale on the roof as the effects of Storm Callum took hold. As you can imagine, this held them up, but it’s all finished now.

It’s a very neat way of creating a flat roof and has a 20-year warranty. It was important to us to have a flat roof, as we want to make the most of our solar PV. To start with, we will fit just enough to get the feed in tariff before it ends next March. Then we will wait until after we’ve moved in and installed battery storage before increasing the number of panels.

The final thing to complete to make the house watertight is the render. We are going for a stark white, in contrast to the black brick detailing, as a design feature. The black bricks look amazing already, and they should look even more striking when the render is complete. This is booked in for the end of November, so we will be watertight well before the winter.

But even without the render, Number 41 looks great. It’s a proper house. It has walls, a roof and holes where the windows will be. You can walk in through the ‘front door’ and walk into all the rooms. Much of the internal studwork has already been created and it makes it very easy to visualise what it will look like when its finally completed.

We have changed our minds on the layout of the master ensuite bathroom. The original design made it feel very cramped when we saw the layout of the studwork, so we have turned the shower 90 degrees to allow ourselves more floor area. One of the reasons we had to get the studwork up at this point was because the bath needs to be fitted very early on. It’s a stone bath and sits directly onto the floor – the waste is fitted underneath. This means to complete the ceiling under- neath, the bath needs installing first.

That all sounds pretty straightforward, but then take into consideration that the flooring has to be fitted before that! And under the flooring there’s the underfloor heating. So we are now choosing tiles for the bathrooms, and we thought we still had a few months before that decision had to be made.

It’s the details that take time. In hindsight, it’s worth taking time at the start to walk through the plans and make any detailed decisions early on. It would have saved us time and cost of making changes during the build.

The internal doors were one of the decisions that was made very easily. We had seen an ad in this very magazine back in January from JB Kind Doors. I had looked them up online and been on the website. The choice was vast, but we knew that to choose right we needed to see them for ourselves. The factory is only about 15 miles from our home, so I got in touch with the company, and we were able to see the complete range in the showroom. It took us less than half an hour to choose. Simon, the sales director came to talk to us as he was really interested in our self-build. He was able to give us some great advice. We have gone for something that’s a design statement – a laminated dark grey walnut wood effect door the Alabama Cinza. We can’t wait to see them fitted.

The knock-on effect of some of the clarifications and changes have put us about six weeks behind. Hopefully we will be able to make up some time now we will be inside. The next steps are the plumbing, electrics and heating. Then it’s the flooring, skirtings and internal doors. Hopefully we will stay on track. Certainly, there are lots more decision to be made.

The original date for moving in was end of February. Now we would really love it if we could be in for Easter, so we will have our fingers firmly crossed over Christmas that we can make up some time.