Damp proofing in Canterbury? Get an independent survey first

Why the survey comes before damp proofing in Canterbury

Damp proofing is the answer to one specific fault, a missing or failed damp proof course, and that fault is far rarer in Canterbury 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 that concern us most in Canterbury are injection and cement replastering on timber framed and flint buildings, and whole house timber treatment on the strength of old flight holes. On the Victorian streets, injection along front walls bridged by raised pavements or gardens is common, and it leaves the cause in place.

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 Canterbury 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.

Canterbury walls, and what they actually need

Timber frames need lime and breathable finishes. Flint and old brick need lime pointing and plaster. Victorian terraces need their courses kept clear and their gutters and airbricks working. Student houses need extraction that copes with the number of people in them. Very few of these need a new damp proof course.

The city sits in the valley of the Great Stour, which divides into branches as it runs through the centre, on river gravels and alluvium with chalk rising on either side. The riverside streets and the meadows towards Sturry are low and wet, with a high water table. The city walls themselves are largely flint and stone, and flint walling is common in older buildings across the district, with the same need for lime and breathability.

• Removing cement and gypsum from timber frames and flint walls and replacing with lime
• Targeted timber repair and treatment only where decay or activity is confirmed
• Clearing ground, gutters and airbricks on Victorian houses
• Extraction sized for occupancy in shared houses

Flint, frames and cement: Canterbury's common mistakes

Two kinds of old wall dominate the historic city: timber frames and flint. Both were built with lime and both were designed to get a little wet and dry again. The damp problems we see in them almost always trace back to a twentieth century repair that stopped that drying: cement render on a frame, cement pointing on flint, gypsum plaster inside, or an impermeable paint over the lot.

Damp proofing firms often propose injection and a waterproof plaster in response, which seals the wall further. The better approach is to reverse the harmful repair, carefully and with consent where needed, and to deal with rainwater and ground levels. It is usually less expensive, it suits the building, and it lasts.

On the Victorian streets beyond the walls, damp proofing is quoted for front walls bridged by raised pavements and gardens, and for mould in shared houses. The first needs the ground dealt with; the second, ventilation and heating.

Damp proofing done properly, in the right order

• Find the cause: measure, look outside, rule the alternatives in or out
• Fix the cheap external faults first and give the wall time to respond
• Only then, if a timber frame, flint and brick or brick wall is still wet at low level with no working course, consider a new damp proof course
• Replaster with materials that suit the wall: lime on old solid walls, never cement on soft brick or stone
• Ventilate and heat so the wall can dry, and check it again after a season
• Keep the paperwork: diagnosis, specification, guarantee and the readings after

How to avoid being oversold

• Never sign on the day of a free survey. A genuine problem will still be there next week
• Ask what else could cause the readings, and how each alternative was ruled out
• Ask for the readings in writing, with where they were taken
• Be wary of whole house treatment for damp found on one wall
• Be wary of tanking or a membrane on an above ground wall that is wet from outside
• Get an independent survey on any Canterbury job above a few hundred pounds; it often costs less than the plaster you would lose

When a damp proof course is the right answer

There are walls in Canterbury 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.

Our survey fees are published on the prices page and fixed before we visit. Set against a damp proofing job on a Canterbury 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.

Canterbury buyers range from families buying period houses to investors buying student lets. On a historic house, an independent survey sets out what is active and what is historic before a treatment firm prices the lot. On a let, it separates building defects from condensation driven by occupancy, which matters under landlord duties and for tenancy disputes.

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 Canterbury 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 Canterbury.

Around Canterbury

Within the walls

Timber framed and historic buildings, many listed, often shops or offices with flats above. Non invasive surveys and conservation minded recommendations are the norm.

Wincheap, St Dunstans and Northgate

Victorian terraces, many let. Ground levels, gutters, airbricks and condensation in multi occupied houses are the usual causes.

Hales Place, Thanington and Sturry

Twentieth century housing and older village cores. Mould, extraction and bridged courses dominate on the estates; groundwater near the Stour.

Damp proofing questions in Canterbury

Nearby

• Damp proofing in Whitstable
• Damp proofing in Herne Bay
• Damp proofing in Faversham
• Damp proofing in Ashford

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 Canterbury and the villages around it.

Book a Survey or call 07386 225526