Damp proofing in Chatham? Get an independent survey first

Why the survey comes before damp proofing in Chatham

Most of the walls we are asked to look at in Chatham after a damp proofing quote do not need a new damp proof course. They need the water dealt with at its source: a path lowered, a gutter cleared, red and yellow stock brick repointed in the right mortar, or a fan that actually extracts. Injecting a wall that is wet for another reason costs real money and fixes nothing, and the tide mark returns once the new plaster dries out.

On the hillside terraces, the quote we see most is injection along the rear and party walls and a metre of replastering. The rear wall is wet because it holds back the hill, and the party wall rarely has any ground against it at all. On the estates, mould on a bedroom wall gets quoted for injection or a "condensation package" that includes a damp course, when the problem is cold bridging and extraction.

Injection, tanking, membranes: what they are for

Injection is for rising damp: groundwater drawn up a wall that has no working course. Tanking and cavity drain membranes are for walls below ground that hold back soil and water, such as cellars and basements. Salt resistant replastering is for walls where years of damp have left salts in the old plaster. Ventilation is for condensation. A quote that applies one of them to the wrong problem will fail however well it is installed.

In Chatham the commonest mismatch we see is injection and a cement based replaster on a wall whose real trouble is outside: open joints, raised ground or a leaking downpipe. Fix those and the wall often dries without anything being injected at all.

Chatham walls, and what they actually need

A Chatham terrace is solid stock brick in lime, usually with a slate course that still works at the front. Below ground on the uphill side it needs drainage outside and, where a room sits below the level of the yard, a proper below ground solution rather than injection. A post war house needs its damp proof course left alone and its ventilation and cold spots dealt with.

Chatham is chalk under a thin cover, cut by dry valleys that run down to the Medway. The slopes are steep, so water moves quickly downhill at the uphill side of terraces in heavy rain. The valley floors and the riverside are lower and wetter, and the Walderslade valleys collect surface water from the estates above. Chalk also has a habit of forming solution features and old workings, which occasionally show up as settlement and cracked drains rather than as damp, but a cracked drain under a house can be both.

• Re laying rear yards to fall away from the house, with a drainage channel at the wall
• A drained cavity membrane only where a habitable room genuinely sits below external ground
• Investigating drains on steep plots where damp appears in one sharp patch
• Ventilation and cold bridge fixes, not damp proof courses, for mould on the estates

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 Chatham 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 Chatham house?
• Can I have the survey in writing before I decide?

When a damp proof course is the right answer

Genuine rising damp exists, and when the survey finds it the report specifies the remedy plainly. The test is not a meter reading but a pattern: damp highest at the base of the wall, falling with height, present on walls with no external fault, and present in summer as well as winter. In Chatham we find that pattern on a minority of the walls we are asked about.

Our survey fees are published on the prices page and fixed before we visit. Set against a damp proofing job on a Chatham house, which typically runs to several times that once plaster removal and making good are included, the survey is small. When it shows that a wall needs a gutter repair rather than an injected course, it pays for itself several times over.

Chatham offers some of the most affordable houses in north Kent, and many of them are Victorian terraces on slopes. A homebuyer report that recommends a damp specialist is common on these. Before exchange, an independent survey establishes whether the damp is lateral water from the hill, a yard falling the wrong way, a leaking drain, or nothing more than salts, and what each 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 Chatham 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 Chatham.

Around Chatham

Luton and the hillside terraces

Victorian terraces stepped into the slope with rear yards against the hill. The survey concentrates on what is happening on the uphill side: ground, drainage and how the yard falls.

Walderslade and Lordswood

Post war estates on the plateau with cavity walls and concrete floors. Mould, streaming windows and cold walls dominate, and the measurements decide whether it is the house or the habits.

Chatham Maritime

Modern flats and houses on the old dockyard. Mould here usually traces back to ventilation that was never commissioned or has been turned off, or to a detail at a balcony or threshold.

Damp proofing questions in Chatham

Nearby

• Damp proofing in Rochester
• Damp proofing in Gillingham
• Damp proofing in Aylesford
• Damp proofing in Maidstone

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 Chatham and the villages around it.

Book a Survey or call 07386 225526