Advice & Guidance
Winter Checks
Winter can be a tough time for old buildings (as well as for people!) as the weather plays an important role in the decay of structures.
Prolonged
exposure to acid rain can start to dissolve some limestones and will also
corrode metal ties and fastenings.
Driving rain can penetrate deep into solid walls where the pointing is
missing or decayed and condensation in a poorly ventilated building can lead to
mould growth or encourage decay in timberwork.
Frost can also contribute to the break down of building materials. If there is too much moisture in porous walling materials this can freeze in winter. As the moisture freezes it expands and can shatter the surfaces of old bricks and tiles. This process can have a dramatic effect if the freeze/thaw cycle is repeated a number of times over the winter season.
High winds and stormy conditions may also cause problems as slates, tiles and leadwork can become dislodged. For this reason it is always worthwhile carrying out an inspection of any vulnerable areas after heavy rain, strong winds or snow.
You should pay close attention to roof coverings and any metal flashings at roof junctions as problems in these areas may provide a route for water to penetrate into the building. You should also inspect accessible roof voids for any sign of water ingress after heavy rain, but only if it is safe to do so.
Winter checklist
Clay
tiles, natural slate and stone: Check all roofs for
frost, snow and wind damage. Not all
colour changes, minor cracks or delamination (flaking) mean that the
roof is in
poor repair, but debris on the ground from broken slates and tiles might
indicate a problem. Have dislodged or missing
slates and tiles reinstated before damage occurs to roof timbers or
ceilings. This is a straightforward task
but will require a contractor who has the appropriate equipment to allow
access
to the roof slope.
Gutters and downpipes: Check that gutters and downpipes have not been damaged by frost. If there is a blockage in a cast iron downpipe, the trapped rainwater may crack or shatter the downpipe if it is allowed to freeze.
Furthermore, if
gutters or hoppers allow
water to discharge over the wall surface the moisture that has saturated
the
surface of the masonry may freeze in cold weather and cause further
damage. Signs of soil being washed away at ground
level or splashes of soil on the base of the walls can be an indication
that
the water is not being caught by the gutter.
Stains on brickwork or masonry that are visible when the weather is dry are also an indication that there might be a problem.
Parapet and valley gutters: Roof valleys and parapet gutters should have been cleared of autumnal leaf fall before the start of winter. In cold weather, any water that cannot drain away is liable to freeze, causing damage to gutter linings when it expands. During the winter, parapet and valley gutters also need to be cleared of snow to prevent melt water rising above them and causing damp internally.
Use wooden or
plastic tools for snow clearance to avoid damage to leadwork and take
extra
care to ensure your safety in icy conditions.
You might also consider having a suitably qualified electrician fit
heating tapes in inaccessible gutters.
These tapes are activated during cold weather using an external
thermostat and warm up to help snow and ice melt away. This prevents a
build up of snow around
hopper heads or against flashings.
However - be warned - heating tapes need to be maintained too!
Access: Duckboards are useful as they allow a space for melting snow to flow away whilst maintaining a safe and dry walkway in gutters and across other areas of flat roofing. Inspect any duckboards to ensure that they are in a good state of repair and have them repaired or replaced if necessary. Remove trapped leaves and other debris from underneath duckboards to ensure that water can drain freely from the roof.
Heating systems: You should ensure that all exposed water tanks and heating pipes are protected against severe frost. Check that the frost thermostat is working correctly too. Localised flooding through pipe or tank bursts, caused by winter freezing, can be prevented by proper lagging.
Further information
Ecclesiastical Insurance Group has produced a ‘Winter Risks' guide that you may also find useful.
© SPAB 2011
