Damp Survey
Report.

This property has three separate damp mechanisms running at once, which is why previous attempts to treat it as a single problem have not worked. There is genuine rising damp to the front wall where the original slate damp proof course has been bridged by a raised pavement level. There is penetrating damp to the left elevation caused by a defective gutter joint discharging onto the brickwork. Separately, there is surface condensation in the bathroom and the front bedroom driven by a lack of ventilation. Each needs a different remedy, and treating one will not resolve the others. The recommended sequence is external repairs first, then the damp proof course, then internal replastering, and only then redecoration.

Survey Overview

A damp survey was carried out at 24 Marchbank Road, Lincoln at the request of the owner, following reports from the occupier of persistent staining to the front wall of the lounge and recurring mould in the bathroom. The inspection was non-invasive and visual, and covered all accessible internal rooms together with a full external inspection of the roofline, rainwater goods, ground levels relative to the damp proof course, and surface water drainage. Moisture readings were taken at low, mid and high level on all affected walls using a calibrated protimeter, and relative humidity and air temperature were recorded in each room. The property was occupied and heated at the time of inspection.

Summary of Findings

The property is a late Victorian mid-terrace of solid brick construction, approximately 225mm thick, with a suspended timber ground floor to the front rooms and a solid floor to the rear extension. Three distinct damp mechanisms were identified.

First, rising damp to the front wall of the lounge and hallway. Moisture readings at skirting level reached 28% WME, falling to 12% at one metre and to background levels above that. This declining gradient with height is the signature of ground moisture rising through the masonry. Externally, the pavement has been resurfaced and now sits approximately 40mm above the original slate damp proof course, bridging it directly.

Second, penetrating damp to the left elevation. A failed joint in the cast iron gutter above the kitchen window is discharging onto the brickwork during rainfall. The affected area internally shows a localised patch of high moisture at high level, unrelated to ground level, with salt deposits and blown plaster consistent with repeated wetting and drying.

Third, surface condensation in the bathroom and front bedroom. Relative humidity was recorded at 71% in the bathroom with no functioning mechanical extract, and light mould growth was present on the cold outer wall behind the wardrobe in the front bedroom. This is a ventilation problem, not a groundwater problem, and would not be improved by any damp proofing work.

Occupier Comments

The occupier reports that the staining to the lounge wall has been present since they moved in and has been painted over twice, returning within a few months on each occasion. They report condensation on the bedroom windows most mornings through the winter, and that the bathroom does not have a working extractor. The property is heated by gas central heating which is used in the mornings and evenings. Washing is dried indoors on an airer in the back bedroom during winter. No vulnerable occupants were reported at the time of survey.

24 Marchbank Road is a two bedroom late Victorian mid-terrace of solid brick construction, approximately 225mm thick, under a pitched slate roof with a single storey rear extension. The front rooms have a suspended timber ground floor over a shallow void; the rear extension has a solid floor of later construction. The original damp proof course is a slate course visible externally at two brick courses above the front path. The property is in generally sound structural order and the rear elevation, rear extension and both bedrooms other than the front bedroom presented no damp concerns.

Primary Remedial Works

• Repair the failed gutter joint on the left elevation above the kitchen window, and check the full run for further defects while access is in place. This must be completed before any internal repair to that wall, or the damage will simply recur.
• Reduce the external ground level along the front elevation to re-expose the original slate damp proof course, achieving a minimum clearance of 150mm below it. Where the pavement cannot be lowered, form a drained channel against the wall to break the bridge.
• Install a mechanical extract fan to the bathroom, humidistat controlled and ducted to outside, sized to meet current Building Regulations Part F.
• Allow the affected walls a drying period after the external works are complete before any internal replastering is carried out. Replastering a wall that is still wet will trap the moisture behind the new finish.

Recommended / Longer Term

• Once the external works are complete and the wall has dried, hack off the affected plaster on the front wall to 300mm above the highest tide mark and replaster using a salt retardant renovating plaster system. Standard gypsum plaster applied over salt contaminated masonry will fail.
• Where the slate damp proof course cannot be re-exposed, install a chemical injection damp proof course to the front wall in accordance with the manufacturer's instructions, followed by the replastering specification above.
• Renew the skirting boards to the lounge and hallway front wall, which are decayed at their lower edge and will not survive removal.
• Retrofit trickle vents to the front bedroom and bathroom windows to provide permanent background ventilation.

Occupier Guidance

• Avoid drying washing indoors on an airer where possible. A single load of wet washing releases around two litres of water into the air of the property as it dries.
• Leave a gap of at least 50mm between furniture and external walls, particularly the wardrobe in the front bedroom, so that air can circulate and the wall surface stays closer to room temperature.
• Keep the bathroom door closed while bathing and for twenty minutes afterwards, and run the new extract fan throughout, so moisture is removed at source rather than migrating into the bedrooms.
• Maintain a low background heat through the winter rather than short intense bursts. A wall that never warms up will continue to attract condensation regardless of how much the room is aired.
• Do not redecorate the affected walls until the remedial works are complete and the plaster has dried. Painting over the staining will not stop it returning, as the previous two attempts have shown.

The reason this property has resisted previous attempts at repair is that it does not have one damp problem, it has three, and they require different remedies. Painting over the lounge wall was never going to work, because the moisture is arriving from the ground and will continue to do so until the damp proof course is no longer bridged.

The correct sequence matters as much as the works themselves. The gutter repair and the ground level reduction come first, because both are the sources of water. The walls then need a drying period, and how long that takes will depend on the weather; a solid brick wall of this thickness typically needs several months. Replastering follows, using a salt retardant system rather than standard gypsum, because the salts left behind by years of evaporation will otherwise draw moisture back into the new finish. Redecoration comes last.

The condensation in the bathroom and front bedroom is a separate matter and can be dealt with immediately and independently. The extract fan and the trickle vents will make a measurable difference within weeks, and the occupier guidance in this report supports that. Once all three mechanisms have been addressed the property should remain dry, and the staining should not return.

Limitations and Use of Report

This report is based on a non-invasive visual inspection on the date stated. No intrusive or destructive investigations were undertaken and concealed areas were not inspected. No laboratory testing, air sampling, or invasive moisture testing was carried out. Findings represent conditions at the time of inspection only and should not be relied upon as a guarantee against future defects. This report provides general guidance on observed damp and mould conditions; it does not constitute a structural or full building survey. Further investigation may be required if conditions change. Moisture readings are indicative and not absolute measurements of material saturation. This report is prepared for the sole use of the client commissioning it and The Damp & Mould Man accepts no responsibility to any third party for its contents. SPECIMEN REPORT. This document is an illustrative example produced by The Damp & Mould Man to show the format and depth of our survey reporting. The property, its address, the client and the findings described are fictional and do not relate to any real property or person. Photographs are taken from our own past remediation work and from our reference library, and are included to illustrate the type of evidence a real report contains.