We may have descended from the cave man but we have moved on, and these days people are put off buying homes which don’t have plenty of natural light. If you build an extension or put in a loft conversion which throws an area of the house into darkness some of the value you added from the improvement will be lost. Commercial properties are also often in need of more natural light and there is good evidence that a shot of day light into your system improves productivity. Many schools are now opting for increased natural light which is not only beneficial to students but helps reduce energy bills.

A classic case that builders come across all the time is the addition of a single storey extension with a flat roof. No matter how big the patio doors are there will be a dramatic fall off in light as you reach the innermost part of the building. It doesn’t even help when the sun shines because the brighter light at the end of the room just makes the inner area look darker. What you need is an even distribution of light throughout the building and, as I found out, there is no easier way than putting in daylight ducting. The rigid tube gives more light than flexibles, and if you have an easy route then SolaTubes are a good bet. The company can supply extension pieces and bends if you have to do something a bit more complicated but short and straight is best if you can do it.

Many builders shy away from breaching a flat roof but these days with high performance sealants there is no need to worry about leaks. The first unit took me two hours to put in because I was photographing it and a little nervous about achieving the right position. The second unit took 45 minutes to put in. I used the larger 305mm units, which left very little room for errors in the 400 centres of the roofing joist. It is easier just to cut a line between the joists and then centre the tube on the line rather than committing yourself to a position from below and finding a joist in the way.
If you don’t know the joist positions use a metal detector to find the line of fixings.

The bottom section can be held in by the swivel clips but I found that the insulation needed to be cut away to allow them to swivel around. If you place some timber noggins in behind the board you can screw into these. The screws are covered by the snap on diffuser plate.

I cut across the roof first to find the joist and counter battened firing pieces then centred the flashing kit on the cut line.

The flashing instructions call for intermediate holes to be drilled to stop the long edges lifting.

After a dry fit I marked the position of the flashing to make sure I didn’t have to move it around on the mastic.

You need a thick ring of polyurethane sealant around the insides of the flashing.

You also need a ring of mastic on the felt around the hole.

Screw the flashing down with the screws provided. Unfortunately there aren’t enough screws supplied for the extra intermediate holes.

Clip the reflector into the north side of the dome. Don’t forget to peel off the protective film – I have seen people leave it on and it cuts the light down by 50%.

The top section fits on a rubber seal and should be screwed in on four sides. The polycarbonate dome presses into position.

The plasterer had not yet been but the diffuser trim is easily removed for plastering and decorating.

FOOTNOTE
It was my original intention to lay a circle of torch-on felt over the top of each flashing, and it is possible to seal to the deck and felt over the aluminium flashing in this way, but I decided against it. Any water ingress on the top dressing of felt would then sit under the felt rather than running off. The way it is now you can see immediately if there is any defect in the sealant.

For further information on any of the manufacturers mentioned in this article visit the following sites:
www.solatube.co.uk
www.dewalt.co.uk
www.dickiesworkwear.com
www.hilti.co.uk
www.fristads.com