Solar P.V. installation

Why install solar p.v.

Up until the begining of this year it was pretty much a no brainer to install solar p.v. on a house, particularly a new build if you could afford the initial outlay as the Governments Feed in Tariff paid good money for power generated regardless of you using it yourself. That all changed this year as the F.I.T. payment dropped to 3.9 pence per kwh, making any payment for generation only a few hundred pounds a year at best.

I did consider dropping any solar p.v. installation but felt that overall it was still a worthwhile thing to do.

Now that there is no money to be made from a solar p.v. investment, actually using the electricity at source becomes more of a priority. This is not as easy as it sounds as generally you want electricity at times of the day when none is being generated. I will be diverting excess power to an immersion heater to heat my hot water, which should provide pretty much all of my hot water needs for half of the year. It is also possible to use timer delays on high consumption appliances such as washing machines and dish washers so they come on in the middle of the day. And as I work from home my energy use during the day for computers, lighting etc should be covered.

Another cost saving on installation is the cost of roof tiles. I chose to use an integrated roof system that fits flush with the tiles rather than mounted on top of them, saving just over £1000 in tiles alone. The solar panels themselves are all black with black trim and no visible silver lines across them so should be as discreet as is possible on the roof. The area of roof where they are mounted is directly south facing and on the rear of the house, so not visible at all from the road.

Power storage is often mentioned, especially by solar companies trying to up-sell, but the reality is that at the moment there is no financial justification for installing batteries. This may change in the future but it seems a long way off.

My planning permission came with a condition to generate 10% of the energy consumed by the house on site. The planners agreed in principal that they would drop this as I was building a house with such a low energy requirement, but I decided to go ahead anyway.

If I was only going to live in the house for a short time the cost of solar really wouldn’t stack up, but as I am her for the long term it will hopefully be a sensible use of a few thousand pounds.Installing flashings to bottom edge of panels

Plastic support panels fixed to battens

Flashings around panels

Flashings around panels

Installation completed

Solar array set into tiled roof


Fixing roofing felt

Fixing roofing felt

Nailing roofing battens


Tiles loaded on roof

Lead work to box gutter

Tiling the valley


Fitting roof lights

Pointing the ridge

Tiles around flush P.V. panels

Fiberglass balcony and box gutter

Balcony covered in OSB before fibreglassing

Timber frame wall panels

Ground floor

Ground floor wall panels

Crane lifting panels

Fixing steel post

Ground floor wall panels

Fixing base of corner post

Fixing ground steel floor beams

Ground floor steel beams ready to start fixing joists

Floor joists over ground floor panels

Metal web joists over living space

Air tight membrane over joist ends

The guys at MBC started fitting airtight membrane and tape right from the start of the frame erection as this is the only way to get a really airtight house. It is too late to try and block up holes and cranks once the frame as been erected, which is the method used by most builders. Before the joists were fitted an airtight membrane was taped to the top of the ground floor walls and wrapped over the end of the joists to be taped to the inside of the first floor walls.Steel beam junction

One of the critical elements of a passive house is not to have thermal bridging of the insulated layer. All steel work is kept to the inside leaf of the frame, allowing good coverage of insulation around steel and keeping it on the warm side of the build.

First floor

First floor wall panels

Lifting first floor steels


Roof trusses being lifted

Roof trusses being installed

Roof topped out

Timber frame arrives on site

The first delivery of the passive timber frame from MBC Timber Frame Ltd arrived this morning from the factory in Ireland. The access to site is quite tight so MBC had arranged to have their truck met by a smaller vehicle and transfer the load a couple of miles away so it would not block the road. The smaller vehicle was still actually pretty large and managed to take the load in just two trips, but with a fairly hair raising few moments each time trying to fit through the gates. The drive has pillars either side of the gate and is also not level. We had to use planks to raise the low side of the truck to level it off to allow it to drive through, still with only an inch or two either side.

Transferring the first load

First delivery arriving

Squeezing through the gate

Unloading wall panels

Panels stacked on the slab

Setting out sole plate

Setting out sole plate

Positioning sole plate and damp proof course

Drilling fixings for sole plate

Before the timber frame wall panels can be fixed in place a timber sole plate is fixed down to the slab over a plastic damp proof membrane (dpc) strip. The sole plate must be accurately set out as the walls will follow its line around the building. It gives a secure fixing point for the wall panels and the dpc prevents any damp rising up into the wall.