Dryfix News

Failed concrete damp proof membrane repair

May 13th, 2019

All posts, Damp / Rising Damp / Damp Proofing /, Surveying


One of the problems with in-situ remedial repair is they are regularly ill considered by their installers and usually recommended by those who are hoping to make a quick buck for half the work required to undertake a repair properly, or have intensives to recommend products sold from a specific manufacturer as oppose other alternatives. One of todays surveys was a prime example. A solid constructed floor absent from a damp proof membrane and suffering from the effects of capillary bound moisture.

The floor has been repaired in-situ prior with the application of a surface bitumen membrane followed by a protective floor leveling screed, yet still displays symptoms similar to those before the repair. So why, whats failed and what options we’re available?

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Scenario – Damp concrete floor – options available………………..

– Remove and replace in like for like concrete incorporating a DPM and insulation in accordance with building regulations.

– Remove and replace in alternative method of construction.

Advantages – Problem solved in its entirety, improved method of construction, thermal improvements.

Disadvantages – Costly, disruptive, time consuming. Disruption may also require additional works such as; cleaning and redecoration afterwards.

Alternative considerations

– In-situ remedial repair such as the application of a surface membranes, resins or barriers (too many to list them all).

Advantages – Usually cheaper than replacement, minimal disruption, minimal time for application.

Disadvantages – does not resolve the initial causation and could lead to additional problems occurring in surrounding structures, potential risk of failure if ill applied or considered.

In this scenario the floor structure was beyond economical repair and in no suitable condition to receive the application of a surface membrane, hence its failure, however, there are multiple other reasons why a surface membrane in this scenario could fail.

In nearly every example I see, the client has received poor advice from the installers and its easy to understand why. As an unfamiliar client when faced with the possibility of uplifting and replacing a floor at great expense and disruption the suggestion of a much cheaper and less disruptive alternative, naturally sounds appealing.

A lack of knowledge by the installers and failure to fully understand the method of construction, causation and consequential effects, however, inevitably lead to these in-situ repairs failing as has happened in this scenario. This then leaves the client in a worse position than they were prior, having now wasted an initial sum of money on a failed repair.

At Dryfix if we ever specify replacement over a remedial repair, we guarantee this is recommended in your interests and that we have considered all other options available. Our recommendations are based on a guaranteed solution considered together with our other obligations such as; cost, time and disruption.

#falseeconomy #goodmoneyafterbad #failedrepairs #right1sttime #Dryfix #YorkshiresLeading #Damp&Timber #Specialists



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