Photo of a guarantee

When is a waterproofing guarantee not a guarantee?

Photo of a guarantee

Most waterproofing guarantees are issued by either a manufacturer / supplier or a contractor referring to a manufacturers guarantee, or an insurance backed guarantee.For the most part these guarantees do not offer any real benefit to the client and can leave the client and or the design team with financial loss, a delayed program or much worse.Insurance companies deal with many millions of pounds worth of claims with regards to basement flooding. Most are covered by worthless guarantees.
A guarantee is only a proper guarantee if it comes from one company covering design, materials and installation.
The client will always want a meaningful guarantee, but most fall well short of meaningful. If it does not cover design, supply and installation it is not going to protect the client, the main contractor or the design team.
The biggest cause of ongoing, expensive & disruptive problems is the manufacturer guarantee. They look reasonable on the face of it but the terms will explicitly limit the guarantee to the cost of replacing the materials. They will not cover investigations, remediations and loss.The manufacturer will offer design and details but will not accept any liability for installation.
The manufacturer may offer to carry out inspections and even on site training, but in the event of a problem they will be very clear that they do not have any liability for remediation.
Insurance backed guarantees only come into effect if the contractor has ceased to trade and are limited to the cost of the original contract. MacLennan guarantees are insured product warranties. They cover design, supply and installation. All design is covered by our 10 million PI. No split responsibility, no argument no risk to client or design team.
To protect the client and all other stake holders from split responsibility insist on an insured product warranty from MacLennan. Our product is not the materials used. Our product is a permanently dry basement. That is guaranteedThe MacLennan warranty is the best available in the industry. It is your USP. The guarantees cover all work carried out by MacLennan including design, materials and installation. All other warranties from competitors and manufacturers and additives companies specifically exclude consequential costs. All manufacturers and competitors and additive companies limit their guarantee to the cost of the work or in the case of manufacturers the materials supplied. Manufacturers may accept liability for design but not for installation. This creates split liability and responsibility and so the work is not effectively guaranteed.

Reasons to use MacLennan for your Waterproofing contract.



MacLennan are one of the very few contractors with a Products Insurance scheme which covers all aspects of the waterproofing installation. All manufacturer schemes cover up to the value of the materials used only, and they do not cover installation.


MacLennan take on design liability and have 10 million PI.


MacLennan are a safe contractor and have won awards for site safety. MacLennan managers are IOSH, All supervisors are SST, All staff are CSCS and most are NVQ2.


MacLennan complete 200 projects per year from £5,000 - £1.6 million. MacLennan have dedicated site and contract managers, who control quality, preparation, and sequencing of work.


MacLennan designers are CSSW. This is a requirement of major insurers. Some are qualified Civil Engineers, most have over 30 years’ experience.


MacLennan have delivered some of the most technically challenging waterproofing contracts on some of the largest and most iconic buildings in the country - on time and within budget.


MacLennan win most of their work through competitive tender. We tell you all of the cost up front. There are no hidden extras with a MacLennan design and quotation.


MacLennan take the risk out of waterproofing.

Ian MacLennan CSRT CSSW
Managing Director

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