Standard Damp Proofing – Windsor SL4

The client instructed Garratt’s to conduct a damp survey and offer considerations related to any remedial works as required. The property was an Edwardian two-bed terrace that was constructed of nine-inch solid brick walls, timber suspended floors, clay-tiled roof and pebble-dashed render. The external appearance suggested a well maintained and updated property.

The Dampness:

Internally, several walls of the ground floor showed visible disruption and spoiling due to dampness.

Rising Damp: Protimeter moisture meter readings taken were consistent with the profile of rising damp up to 800-900mm from floor level.

High Ground Levels and Bridged Damp Proof Course: The external ground levels to the front of property had risen above the physical damp proof course (DPC) over the years and had led to bridged rising damp affecting this particular area. Where high ground levels are present, there are two options;

1) lower external ground levels using a dry zone channel with pea-shingle where economically viable and then damp proof the internal wall/s or

Visible/wet dampness is usually due to penetrating damp and/or condensation rather than rising damp which is rarely visible

2) apply a cementitious tanking system to internal wall/s, this application is regularly used in basements and lower ground floor areas.

Incorrect Plaster: The wall under the open staircase had undergone works in the past that had utilised lightweight plaster (Bonding); such finishes can and will often absorb internal water vapour where condensation exists. Moisture readings were noted at higher levels on the wall here.

The Recommendation:

Bridged DPC: allow high external ground levels to remain, apply chemical DPC, tanking system and skim finish to the internal side of front wall up to 1.2 metres.

Rising Damp: apply chemical DPC, waterproof render and skim finish to dry zone side of front wall up to 1.2 metres.

Incorrect Plaster: apply chemical DPC, waterproof render and skim finish to full height in the area under open staircase

The Execution:

Understairs and Rear Reception: where full height and 1.2M standard damp proofing was conducted.

Before: Sticky back carpet protector to stairs, corex board protection to the whole of floor carpet and polythene dust screen to lessen dust migration to kitchen area.

During: All traces of lightweight (bonding) plaster and render removed to full height.

This was a party wall and not external. The services were left connected (per client request) for us to work around in this instance.

Applying waterproof render to prepared brickwork, the render was left overnight in order to set and begin curing ahead of the final task.

After: multi-finish plaster skim, followed by clean up and protection removal. Skirting boards (previously set-aside) will require re-fixing once curing is complete (note plaster skim not taken to floor level, this is quite normal and standard practice in building works).

Front Reception: where a combination of cementitious tanking and standard damp proofing was conducted.

Visible dampness noted to wall prior to works, this can also be seen on some of the exposed brickwork. The chemical DPC injection can be seen to lower wall in the right-hand picture. The metal back boxes for electric sockets can be seen partially removed, these got embedded in waterproof render during works. Occasionally we need to replace rusted back boxes that present themselves during works.

Dirty, major works mitigated with pre and post works care, one happy customer;

“Morning Megan

    I just like to thank Tom & the team for a great job and the time they spent covering carpets and furniture and stair  

    Well excellent and not forgetting you people in the office thankyou.

    The cheque has been sent. And I like to wish you all a very merry Christmas & new year.

               Kind regards”

Via email 28^th Oct, the first Christmas wishes of the year.

We hope we can offer the same well-rounded and professional service to yourself one day.