Structural Warranty.

This page tries to explain what to expect from a structural warranty.

First, the problem you are still likely to encounter.

Your structural warranty provider is likely to want an insurance backed guarantee, IBG, for basement waterproofing.

It is simple, though expensive, to have an internal drainage system, IDS, inside your basement and to get an IBG to give to the warranty provider.

But IDSs don't cope with nor guarantee against mud. Mud comes in during heavy rain, blocks the pump, rain continues, basement floods, neither insurance pays out.

That is why the current Approved Document BS8102:2022 forbids IDSs as a waterproofing measure in a new domestic basement.

Your contractor must repair all leaks completely, that is what the Standard requires. I have other pages going into the details.

But the insurers have yet to catch up. None of them seem to offer an IBG for a basement inspected and known not to leak anything even after a period of heavy rain.

Structural warranties, as far as I know, never include beneath ground waterproofing in their cover. The solution seems to be contract your contractor to fix all leaks until they successfully pass a thorough inspection, and persuade your warranty company not to insist on re-insurance, the IBG, for what they don't insure anyway.

I quote several sources below.

A structural warranty covers pretty much everything but specific parts that require skill and good workmanship are covered by the installers' guarantees and their Insurance Backed Guarantees, which are then assigned to the structural warranty.

Basement waterproofing falls into this category.

Your newly built basement needs to be left bare until after your roof is on completely and sealed, the same with windows, the basement pumped clear of rain that collected, cleaned and dried, then inspected for leaks after a period of heavy rain.

Leaks need to be repaired and the inspection repeated after another period of heavy rain.

Only now can you cover the basement floor and walls. If you plan to paint the inside of the basement with a vapour barrier, this had to wait as well. Your two defences would be waterproof concrete and vapourproof paint inside.

Caution: The full cost of a structural warranty could be the cost of the structural warranty
+ the cost of an Insurance Backed Guarantee for basement
waterproofing
+ the cost of an Insurance Backed Guarantee for roofing
+ the cost of an Insurance Backed Guarantee for render
+ the cost of an Insurance Backed Guarantee for heating
+ the cost of an Insurance Backed Guarantee for glazing
+ the cost of an Insurance Backed Guarantee for electrics
+ the cost of an Insurance Backed Guarantee for renewables
+ the cost of an Insurance Backed Guarantee for insulation, and
+ the cost of an Insurance Backed Guarantee for general building

In BS8102:2022 no internal drainage counts as a waterproofing measure. The Standard wants a basement to be repaired of leaks and two defences which can be either external drainage, waterproof concrete or vapourproof paint.

If you completely meet with two, or even exceed building regulations and BS8102:2022 with three valid waterproofing measures, then you can add whatever you want. If you or your adviser absolutely insists on internal drainage then, if the basement is known not to leak, you can add the very small and simple system I describe on the page for architects.

STOP PRESS.

5th March 2024. Following slow discussions with Protek - a business that promotes its structural warranties and insurance backed guarantees,

An email from their Mr Jack Jackson included "Having reviewed the policy wording I can see that this policy does not cover the below ground waterproofing." "As the policy does not cover enclosed areas below ground we will not require the insurance backed guarantee for the waterproofing of the basement as there is no cover in place for this."

The policy referred to is my client's structural warranty policy.

As far as I know, none of the structural warranties cover beneath ground waterproofing, but a lot of the others, such as NHBC, ABC+ demand an IBC for basement waterproofing despite their not insuring it themselves.

Protek might be a bit simpler and a bit cheaper to deal with.

I have added an insurance case study page you may also find of interest here.

Even if you did the work, if I supervised the waterproof concrete elements, I can guarantee your concrete does not visibly leak and it can be my guarantee that is backed by insurance.

I found this list here.

Latent Defects are normally:

Faults in workmanship
Faults in the Design
Faulty Materials
Faulty Installation
Faulty Construction

Benefits of Latent Defect Insurance:

Cover can be provided for up to 12 years
Structural damage/ defects are covered
Legal and professional fees are covered
Building Components can be covered
Mechanical and Electrical services can be covered

Here are some quotations with links to sources.

From the Build Zone web site here. These quotations make it clear that beneath ground waterproofing is excluded.

Definition: Waterproof Envelope
The waterproof envelope means the ground floors, external walls, roofs, skylights, windows, doors, of a Housing Unit but excluding those parts below ground floor slab level.

F. General Exclusions
h. Ingress of water
Loss or damage caused by the ingress of water into the Basement of the Housing Unit and to those parts of the Structure outside of the Waterproof Envelope.
p. Events normally covered under household policies
Loss or damage caused by or consequent upon fire, lightning, explosion, typhoon, hurricane, cyclone, volcanic eruption, earthquake, storm, tempest, flood, subterranean fire or other convulsion of nature, aircraft or other aerial devices or articles therefrom, escapes of water from tanks, apparatus or pipes, malicious persons, theft, attempted theft or impact.

These two pages make it clear that defects arising within two years of practical completion are not covered
architectscertificate .
Premier Guarantee. Look for the Defects Insurance Period.

This quotation is also from Premier Guarantee.

" Examples of inherent defects can include faults in the design, installation, workmanship and materials that resultantly affect the structural integrity of a building.
Structural warranties cover the full reinstatement value of a property, meaning they will restore the build back to its original specification. "

And this is a link to a page on the Premier Guarantee web site, current at 3rd March 2023. In case it moves or gets deleted, here you can open the .pdf version that was available the same day.

The Premier Guarantee "below ground structural waterproofing risk assessment" refers, in the second paragraph, to BS 8102 (2009).

But that Standard was withdrawn more than a year ago on March 31st 2022 and replaced by an entirely different approach to basement waterproofing: BS 8102:2022.

I know that at least one of my clients needed a structural warranty to get his mortgage but he was able to complete his basement structure before he drew down any funds and that allowed him to somehow only get a warranty for above ground because the lender's money was only tied up above ground.

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