Roof treatment and insulation

Why solar reflective coatings extend the life of felt roofs indefinitely and the benefits of 3 way, reflective insulation.

Roof treatment

Hot rolled felt, (applied by melting a special coating on the underside of the felt with a roofing blowtorch so that it becomes part of the roof and sticks to the entire roof, unlike spot nailing of shed roofs which never lasts), is then coated with 2 coats of solar reflecting finish.

As builders in the past, we researched many years ago into the reasons as to why some house flat roofs seem to last indefinitely and others fail after only a few years. The answer is two fold. 1. Ultra-violet light destroys bitumen and breaks it down, and 2. If the roof has no fall then the water never runs off which makes the roof “an accident waiting to happen”

Even with a flat roof, if the roof is finished off with a solar reflecting finish, then the ultra violet element of sunlight never reaches the felt, so it never breaks down or splits as before, and if a proper pitch or fall is added,the rain runs off and away quickly, never settling and searching. Both these problems are addressed with our roofs,which give a trouble free roof with a very long life.

The felt manufacturers recommend re-painting of the solar reflective finish every 7 years,it costs about £35.00/coat and less than 10 minutes with a roller. Extra Rooms roofs are supplied with 2 dense coats. (One extra to start with) then another as we add the pre-coated sealing strip over the panel joints and go over it all again as we complete assembly in your garden, so three in total.

After 2-3 months the aluminium oxidises in the reflective coating and the roof settles to a matt grey colour, initially however, it has a bright finish as shown here. It also assists in cooling the roof down in summer as a bonus to the insulation.

The insulation we use as standard and an even higher spec variant if you wish.

After years of experience in construction of high class garden offices, we at Extra Rooms have researched, and now supply as standard, insulation which also reflects summer heat away from the building or back into it again in the winter.

Most insulation like fibreglass or polystyrene only deal with heat loss by conduction and convection, but there are three methods of heat loss, the third, which is normally missed is radiation.

40% of heat loss is through radiation, nearly half! It is missing altogether from the equation with most insulations!!

Our standard insulation deals with this by virtue of its double sided reflective aluminium layer which reflects the heat back to the direction it came from, so in summer, it sends the heat away from the building, and in the winter, the warmth from inside is reflected back into the building. Our solar reflective coatings on the roof further enhance the effect.

This, when combined with our construction methods which utilise the sealed 70mm space within our panels to further deal with convection and conduction, plus the extra values of plywood rather than plasterboard, gives our walls and roof and floor panels, with our standard insulation, the high thermal efficiency they have, which far exceeds most competitor's standards.

However, if you wish, we can use an even better insulation if you really prefer, it is actually “over the top” for a single draught proofed sealed room, it exceeds the efficacy of 200mm or 8” of fibreglass by 40%, and to “do our bit” for mother earth we only charge an extra £6.90 per sq ft or £69/sq metre for it if you are wanting to have the highest spec insulation fitted in garden rooms in the UK at present, making yours one of the greenest studios possible.

Whilst these prices are worked out according to the floor area of your extra room, they take into consideration to include this insulation on every surface of your extra room, the floor, all walls and the ceiling/roof, if you wish to have this ultra high spec. It is an amazing product at only about 6mm thick, and not necessary really, but you have a choice and we will provide accordingly, as always.

The solar reflective coating itself is made from aluminium powder in suspension. Just as a new aluminium ladder at first looks and feels as if it is chrome plated when new, so it is for the roof coating, for the first few weeks it looks like it is chrome plated,but just like an aluminium ladder, it soon oxidises and goes a matt, dull grey.

It still retains the qualities it is designed for, that of excluding ultra violet light, (this is why felts deteriorate), but with the coating, no ultra-violet light ever reaches the felt, which is why it retains its properties indefinitely, and does not split or crack.

When complete, the hot rolled felt is in effect melted into one sheet, so it is melted and stuck fast to the roof and can never peel off in heavy winds, which is why we do not use felt tiles, as they can peel off in high winds, plus they suffer from the ultra violet in sunlight and go brittle and fail after a few years.

There is another advantage of using the felt with reflective coating, in reflecting the ultraviolet rays it also reflects the sunlight, keeping the building cooler in summer, just as the reflective insulation does.