Nearly every replacement conservatory roof sold in the UK is an aluminium frame with insulation boards dropped in between the rafters. Ours is not. We use a custom-made timber construction system, cut to your conservatory’s measurements, and there are two reasons that matters once the roof is on.
The first is heat. Aluminium conducts, so an aluminium rafter carries warmth out of the room and cold into it, straight past the insulation sitting around it. Timber does not move heat or cold the same way, so the insulation performs as designed across the whole roof rather than only in the gaps between metal.
The second is moisture. Our build is fully ventilated beneath the tiles, so water vapour that reaches the structure moves out instead of sitting in it. Sealed systems are where condensation forms inside the build-up, and you tend not to find out for years.
The depth of a timber frame also lets us fit a thicker layer of insulation than a metal system has room for. That is how the finished roof reaches a U-value of 0.15 W/m²K. The roof we take off will be somewhere near 2.6. The lower the figure the better the roof holds heat.
You will lose some light. Usually between 5% and 11%. Where a conservatory faces north or sits in the shade of the house next door, we will normally suggest a skylight or two, which brings the loss back to almost nothing and gives you a much better ceiling to look at.
