Damp proofing in Swanley? Get an independent survey first

Why the survey comes before damp proofing in Swanley

Damp proofing is the answer to one specific fault, a missing or failed damp proof course, and that fault is far rarer in Swanley than the quotes suggest. Before anyone drills a wall, somebody with nothing to sell should establish why it is wet. That is the whole of what we do. We carry out no treatment, so the survey is not a route to a sale.

The quotes we see most in Swanley are injection and replastering along the walls of a 1960s or 1970s house that has a perfectly good damp proof course, sold on the strength of black mould and a meter reading. Mould on an upper floor bedroom wall is not rising damp. Neither is damp at the junction with a newer extension, which is a detail fault at the floor or the cavity tray.

The kinds of damp proofing, and what each one is for

"Damp proofing" covers several different jobs. A chemical damp proof course is a cream or fluid injected into a mortar course to stop moisture rising from the ground. A physical course is a membrane or slate cut into the wall, slower and more disruptive. Tanking is a waterproof coating or render that holds water back on a wall below ground. A drained membrane lets water reach the wall and carries it away to a channel and pump.

Each answers one fault. None of them fixes rain coming through brick or brick, a gutter overflowing down a corner, or condensation on a cold wall, and those three account for most of the damp we are asked about in Swanley. Replastering is often sold alongside, and on old solid walls the choice of plaster matters as much as anything injected.

Swanley walls, and what they actually need

Most Swanley houses have cavity walls built with a damp proof course that still works. What they need is the course kept clear of paths and extension floors, cavity trays doing their job over openings and at junctions, and enough ventilation for a modern household. The older cottages in the villages need the opposite approach: lime, breathability and no sealing coats.

The town sits on the chalk dip slope above the Darent valley, with clay with flints and patches of sand and gravel on the higher ground. Water drains steadily on the chalk but lingers on the clay caps, so gardens on the higher estates can stay wet through winter and shed water towards houses on sloping plots. The Darent itself is a chalk stream to the east, and the valley floor at Eynsford and Farningham sits close to the water table.

• Improving extract ventilation in kitchens and bathrooms and checking it is ducted to outside
• Dealing with cold bridges at lintels and reveals where mould forms in a line
• Correcting extension junctions where the floor or the cavity tray bridges the old wall
• Lime based repairs, not injection, on the solid walled cottages in Swanley Village and Crockenhill

Darent valley villages

Eynsford, Farningham and Horton Kirby have historic buildings on the floor of the Darent valley, timber framed, flint and brick, many listed. They sit close to a chalk stream with a high water table, and they need lime and breathability. Damp proofing systems designed for modern brick walls are rarely appropriate and may need consent.

The survey for these buildings looks at rainwater, ground levels, the finishes on the walls and the floors, and recommends repairs that respect the building.

What proper damp proofing should look like

• A written diagnosis first, with readings and photographs, saying why the wall is wet
• External causes fixed before or alongside any internal work: ground levels, gutters, pointing, render
• A damp proof course only where one is missing or has genuinely failed, at the right height for the Swanley house in question
• Salt contaminated plaster removed and replaced with a suitable breathable or salt resistant finish, not sealed over
• Drying time allowed before decoration, because a wall that has been wet for years does not dry in a week
• A guarantee that names the walls treated and the cause addressed, from a firm that will still be there

Questions to put to anyone quoting

• Why is this wall wet, and what is the evidence?
• Have you checked the ground level, gutters and pointing outside, and what did you find?
• Would the damp stop if those were fixed, and how do you know it would not?
• Why this height of replastering, and why this material?
• What exactly does the guarantee cover if the damp comes back in this Swanley house?
• Can I have the survey in writing before I decide?

When a damp proof course is the right answer

There are walls in Swanley that do need a damp proof course. A solid wall built without one, or with a slate or bitumen course that has cracked or been cut through, that is wet at low level with nothing outside to explain it and with the readings falling off with height, is a reasonable candidate. When we find that, the report says so and specifies where and how high, so you can get comparable quotes.

Damp proofing is priced per metre of wall plus replastering, and on an older Swanley house that adds up quickly. The survey is a fixed fee, published on our prices page, and its job is to make sure you only pay a contractor for the metres that need it, if any.

Swanley houses are popular with buyers moving out from south east London, and many come with a homebuyer report noting mould or damp readings. In a post war house, that usually points to condensation, ventilation or a cavity problem rather than anything that needs damp proofing. An independent survey tells you whether there is a real defect and roughly what it would take to fix.

After the survey you have the cause in writing, a list of what needs doing in order, and what does not. If damp proofing is part of it, the report specifies the walls, the height and the finish, so the quotes you collect in Swanley are for the same job. If it is not, you have the evidence to say no to the quote you were given.

For the full picture of what a survey here involves, see damp surveys in Swanley.

Around Swanley

The post war estates

Most of central Swanley. Mould in bedrooms and bathrooms, streaming windows and a musty smell in cupboards on outside walls are the usual reasons for a visit, and the cause is measurable rather than a matter of opinion.

Hextable and Crockenhill

A mix of older cottages and twentieth century houses on larger plots. Ground levels against older walls and the junctions with later extensions account for much of the damp here.

Eynsford and Farningham

Historic villages on the Darent with timber frames, flint and old brick, many listed. These need breathable lime based repairs and a survey that knows what not to recommend.

Damp proofing questions in Swanley

Nearby

• Damp proofing in Dartford
• Damp proofing in Sevenoaks

Book a survey before you pay for damp proofing

Get the cause in writing before anyone drills a wall. We sell no treatment and cover Swanley and the villages around it.

Book a Survey or call 07386 225526