If you have a glass roof on your property, you can successfully carry out repairs yourself. There is a range of products available which make some types of repair work relatively straightforward. For example, cracks in the glass and leaks along the glazing bars, the usual faults in a glass roof, can be sealed with a self-adhesive flashing strip. Alternatively you can use mastic waterproofing tape – it is best to buy a foil-covered type since this lasts longer and is less messy to handle than plain mastic tape. Where you want the repair to be unobtrusive, you can buy a clear glass-sealing tape: this is applied in the same way as the other tapes.
Clean the glazing bars with a wire brush and use soap and water or a detergent to clean the glass, rinsing with clean water. Allow both to dry before applying the tape or strip. The scaling material should be wide enough to overlap the glass and glazing bar by at least 13mm. In the case of a glazing bar, start at the highest point of the bar and lay the tape or strip over the bar, pressing it down on each side. When dealing with a crack, start at the glazing bar immediately above the crack. At glass overlaps, double the tape on itself since this helps to form a watertight joint. If you are joining two pieces of tape, place the upper piece over the lower piece to prevent water seeping in.
Making permanent repairs
For long-lasting repair on a leaking glass roof it is best to remove and renew the glass; you can replace cracked sheets of glass at the same time. Check with your supplier for the most suitable type of glass. After you have lifted the glass, clean and repaint the glazing bars with a waterproof paint and bed the glass back on mastic glazing strips. These are preferable to putty since they never completely harden and allow for expansion. Some metal glazing bars have special clips to hold the glass on the glazing strips; with timber glazing bars, the glass is held down with small glazing sprigs which you drive into the bars, using the flat edge of a wide chisel.
Cracked glass in a skylight should be removed and replaced with wired glass bedded all round on a mastic glazing strip. Check the flashings around the skylight and, if necessary, repair or replace them. Remove any flaking paint from the skylight area and treat the timber with clear wood preservative; when dry. paint with primer, undercoat and at least two top coats.