SAS Urban Survival Handbook Read Online Free PDF Page B

new or sudden movements, generally indicated by a crack of growing length or width, or creases or splits appearing in wallpaper at corners, should be investigated. Recent very dry, hot summers in temperate countries have dried out soils and greatly increased the number of properties affected by subsidence damage.
    Any crack, especially a new one, should be investigated—or even monitored over a period of weeks or months to ascertain the cause. Don’t assume that the building is falling down—but don’t ignore the cracks either. Monitoring may involve marking the crack in some way to work out the direction of movement. A crack in an external wall will let in damp and this could lead to further problems.
    Consult an expert such as a surveyor or a professional builder. Your insurance company may be able to advise, but many policies do not allow for the effects of subsidence and settlement.
     

WARNING
     
    Climbing plants, particularly ivy, should not be allowed to scramble unchecked over the outside of a building. If the walls are in good condition or the bricks and mortar are new, there should not be much problem. The aerial roots will invade bad joints or cracked rendering, expand and severely weaken a wall. Eventually, the weight of old plants (stems can grow as thick as your neck!) could pull a wall down.
    Care should be taken to avoid ivy invading the spaces around the eaves of the house, spaces between slates, tiles, flashing and weatherboarding. As the roots and stems expand they will open up any crack they can find. Remedial treatment may be difficult if the situation has got out of hand.
     

OUTSIDE CHECKS
     
    Take a critical look at your home from outside and in. Make use of a neighbour’s upper windows to help you see the roof. Use binoculars if you can. The most serious damage could lead to collapse of all or part of the building, but anything which lets in rain or damp can start a chain of problems. Paint and other decorative treatments have a vital function in protecting wood and other materials, and require regular upkeep.

Roof
     
    No roof covering is expected to last forever. The effects of the weather and conditions inside the roof space will take their toll. Look for sagging (drooping) roof lines. This may only indicate that, over a long period of settlement, the external walls have stood firm while the internal structure has ‘sunk’ slightly. This may not be serious. However, timbers may be decaying because of inadequate weatherproofing, condensation in the roof space or even infestation of wood-boring insects. Sometimes a new roof covering may be too heavy for the old timbers, or new work—such as a loft window—may be inadequately braced.
    From the outside, try to find a good vantage point such as a neighbour’s upper window—use binoculars from the ground. Look for deformation of the shape and slipped tiles or slates. The latter may be due to failure of the nails holding them in place and could be progressive.
    From the inside, working with a good light (and strong boards across the joists when there is no attic flooring) look for damp and rot. Its location may help pinpoint external problems. It may also be due to condensation in the roof space. All roofs are designed with some ventilation, usually at the eaves, to allow the space to ‘breathe’.
    Wood-boring insects can do very considerable damage if allowed to colonize the roof space. Badly-infected timbers may have to be cut out and replaced. However serious the infestation, all internal timbers should be treated.
    Lead roofs are vulnerable to the extremes of climate. Repeated expansion and contraction will crack the lead, resulting in further problems. Avoid long runs of lead which accentuate the problem.
    All flat roofs must have good drainage. Most felt roofs will blister and trap water, but more damage is done by walking on them, or resting ladders on them, than is done by the weather. Cracked or leaky felt may only need to be