Money Pit or Gold Mine? How to survey old houses for renovation - Part 2

• Read part one

DAMP

You can usually spot damp problems, because of the smell and damage to decoration. Damp conditions lead to rot and infestation of timber and so need to be taken seriously however, the cause of damp is commonly misdiagnosed (particularly rising damp), leading to unnecessary treatments.

Damp problems are often due to leaks, either from missing or broken roof coverings, displaced flashings around junctions, e.g. where the chimney comes through the roof or where an annexe abuts the main structure, or from a blocked or damaged gutter or downpipe. Once discovered, the source of this kind of damp problem is usually obvious and solving it involves a simple and inexpensive repair or replacement, followed by the repair or replacement of any damaged finishes.

If the damp is not from a leak, then it is usually due to one of three causes:

Rising Damp: Rising damp only affects ground floor walls that are in direct contact with the ground where there is no damp-proof course, or one which has failed. It can be detected by a high tidemark at a height of 0.5-1m above floor level, marked by powdery white crystalline deposits. Solving rising damp can be expensive depending on the treatment used the most common of which is chemical injection. This will cost from £80-120 per linear metre, including cutting away damaged plaster from all ground floor walls to a minimum 75mm above the level of the rising damp, repair with render-mix scratch coat and renovation plaster which has moisture resistance and fungicide in it. If the exterior is rendered, this will also have to be removed and replaced at a further cost of £15-25 per linear metre. In concrete, brick or stone floors, introducing a damp-proof membrane beneath the floor finish should solve rising damp problems.

Lateral Damp: This is where water is coming through the walls and into the building. This is typical in an old cellar, or where the ground has built up outside a building above the damp-proof course. Planting or materials stacked up against the walls can also cause this problem. Reducing the ground level against the walls or moving the source of the damp build-up will often solve the problem and is not expensive. It can also be caused by leaks from gutters, downpipes or overflows. Lateral damp is often mistaken for rising damp.

ABOVE: Damp away from the floors and lower external walls is likely to be caused by condensation.

Condensation: Damp on or underneath windows, at the foot of walls or any other cold points in a house is probably caused by condensation. This is damp that has built up from within the building from cooking, washing, breathing and drying out which has not been able to escape due to inadequate ventilation and has, therefore, condensed at the dew point in the walls. Damp from condensation is always found in buildings that have been empty and unheated, and is often mistaken for rising damp, as damp meters cannot distinguish the difference. Before budgeting for rising damp treatment, make sure the problem is not condensation rising damp will leave obvious signs of damage on the walls and salty tide marks.

Condensation problems are common in old buildings that have been modernised by the addition of double glazing, blocked-in fireplaces and air bricks, concrete floors, and central heating. The problem can usually be rectified with increased ventilation levels and this is not expensive.

ASBESTOS

Asbestos was used extensively in buildings up until the 1980s - especially garages, outbuildings and commercial buildings, and to form gutters and downpipes. The form you are most likely to encounter in a renovation or conversion is asbestos cement board, used as a cladding material for walls and ceilings, especially in damp areas. Asbestos has proven links to health problems and consequently its disposal is now regulated. Although you can remove asbestos yourself and dispose of it as contaminated waste in a specially-licensed tip, any subcontractors handling asbestos must wear protective clothing. If you find asbestos, get a contractor to prepare a report and a fixed-price quote for safe removal and disposal. The price will depend on the type of asbestos and the quantity.

OUTDATED WIRING

ABOVE: It's fairly easy to spot the tell-tale signs that a property needs rewiring. It's also worth checking behind modern switch plates to check that the wiring is up to date and that the owner hasn't just made superficial changes.

Tell-tale signs that a house is in need of rewiring are easy to spot. Look for an old-fashioned fuse box instead of a modern consumer unit, old-fashioned round light switches, round pin plugs or out-of-date wiring with no earth core. Signs of recent rewiring are surface-mounted three-pin sockets and switches, evidence of chasing in of wires, and ceiling light junction boxes. If possible, check that someone hasnt just updated the sockets, switches and lighting pendants to give the impression of a rewire, without actually upgrading any of the cabling. Remove a socket or switch plate and look at the wiring modern electrical installations are wired in PVC-insulated cable coloured grey or white. Unless the wiring is the modern PVC-coated type, then a rewire is likely to be necessary.

Rewiring a typical three bedroom terraced house (90-100m²) will cost from £2,500-3,000, including removing the old wiring, lifting and replacing the floorboards, and installing a new consumer unit, but excluding making good the plaster and decoration. The job should take a pair of electricians five to seven days.

FAILED/NO CENTRAL HEATING

Check that the central heating is genuinely in good working order. If not, you will have to budget for a new system. Adding a wet radiator, gas central heating system to a typical three bedroom terraced house will cost £2,500-5,000 and will take a plumber seven to eight days. For a larger house add £400- 600 per room.

• Read part one