From the roof space inside If the inside of the roof is unlined, check
for cracks showing daylight as this will indicate areas needing closer inspection. Shine a
torch on the timbers and check for water staining. If stains are found on the timber, try
to trace the source of the stain. It is useful to inspect the inner roof space after a long
period of rain, as the source of a leak is easier to trace. Slate does deteriorate with age
so check for hairline cracks by looking for staining on the tiles.
From ground level Outside, check the whole roof by inspecting at ground level.
It is easy to spot a disjointed or slipped slate against the regular lines of slates. If
there is a change to the colour of a section, it could be newly exposed and therefore
unweathered. Look for a powdery or flaky surface, known as delamination, which shows
deteriorating slate, which is no longer doing its job effectively. Look at the ridge on the
skyline and check for gaps in the mortar joints. Check for the state of the flashings at
abutments and around chimney stacks. Check for fallen pieces of mortar.
If the roof is too
high to allow you comfortable access by ladder for a closer inspection, use binoculars to
scan the surface as carefully as possible, from all angles - front, back and sides where
applicable.
At the roof level If you are using a ladder, always make sure it is set up
correctly and long enough - at least 3 rungs above the gutter. Always work with someone
standing near by when you are working at a height. See our Ladder Users Guide for details on how to use a ladder correctly and safely.
Once at the roof level, only access the surface of the roof using a roof ladder. This is a
purpose built ladder that has wheels to allow you to push it up the sloping roof without
dislodging or damaging the slates. When the wheels reach the top of the roof ridge, by
turning the ladder over a hook securely lodges on the ridge.
You can hire roof ladders see Hire Shops. Otherwise, there are wheel and
hook sections available to buy which fit onto conventional
ladders. If you are going to be working on the house, perhaps a scaffold tower would be
worth hiring (see Hire Shops).
Should a roof be replaced?
If patch repairs are regularly necessary, it may be time for the roof to be re-covered. It
is difficult for an amateur to judge whether a new roof is required. If you need advice about
the soundness or safety of your roof, contact one or two builders for their opinion.
Alternatively, pay a surveyor or architect for an unbiased report on its condition.
A contractor, who will guarantee the work completed, should undertake major roof repairs or
replacement of sections. It is worth checking with your local authority to see if you
qualify for a discretionary improvement grant. This will depend on the age of your property
plus its rateable value. Planning permission is not required for roof replacements unless
the building is a listed property or you live in a conservation area.
A slate roof is expensive and is often replaced with less expensive tiles. Slate is
available and it is worth checking supplies with builder's merchants, roofing companies or
demolition contractors.
Simulated slates are available and are less costly than replacing
the roof with real slate. Imitation Cornish, Cumbrian, Cotswold and Welsh slate are available
in a range of sizes. Flat ones with nail holes are often suitable for replacement on a slate
roof, but check the size, colour and thickness carefully. Not all simulated slate tiles are
suitable for repairing a slate roof as they are made with nibs and interlocking grooves that
would not fit on to an original slate roof.
The type and colour of the tiles can enhance or spoil the appearance of the house. If you
live in a terraced or semi-detached property, consider the covering of the neighbouring
roof, which can affect the overall appearance of your roof.
