Structural Warranty.

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

But, more important and of much more concern, what problem to expect from the warranty provider during the process.

You will have read on other pages

Building Regulation C2 is the legal requirement, and the legal test is harmful effects.

BS8102:2022 is the Approved Document. If you satisfy the Approved Document, by fixing leaks until there are no leaks, you should not need to explain anything to anyone.

Table 2 of the Standard states that habitable accommodation should be Grade 3: No ingress of water or damp areas is acceptable.

At 3.16 it is defined that internal drainage is not a waterproofing measure.

If you are told not to follow BS8102:2022, by being told to put in a sump and internal drainage system, then the person or body directing you to cover leaks over must justify why and how their alternative to the Approved Document will satisfy Building Regulation C2.

The new Building Safety Act 2022 makes the client or developer primarily responsible for meeting all requirements of build quality. The client or developer remain responsible for mistakes or omissions by their design team and their workforce, to make the client choose very carefully.

The purpose of this page, is to highlight the dangers of installing an internal drainage system because the insurer insisted upon it - putting the client in jeopardy and fear of prosecution.

The new procedures of building control will leave an audit trail so that if any building regulation is breached, the client or developer will be prosecuted and be held mostly to blame. Their principle designer or main contractor might also face criticism, rebuke, or sanctions from the new Building Safety Regulator.

Until they change, this is the headache your structural warranty provider requiring an insurance backed guarantee for a basement will give you.

Your structural warranty provider is likely to want an insurance backed guarantee, IBG, for basement waterproofing. Typically, this is a guarantee, for labour and materials only, for an internal drainage system, IDS. Usually, the internal drainage system installer will cover over all the leaks left by the contractor before anyone else has a chance to look inside the basement.

Two problems. First, that if any sub-contractor sees a sump in the basement floor, they will feel incentivised to leave more and worse leaks. Second, nothing the internal drainage supplier has will stop leaks before they are covered over.

Internal drainage is very expensive. The structural engineer needs to add in a sump pit to his design, the contractor needs to dig and form that sump pit in reinforced concrete. The contractor is unlikely to have any insurance excavating that extra depth and they may find water and horrendous problems.

But IDSs don't cope with nor guarantee against mud. Mud comes in during heavy rain, blocks the pump, rain continues, basements flood, there is mould, and the occupants suffer harm. The DEVELOPER has broken many laws and faces prosecution. Neither the IBG or warranty insurance pays out.

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.

If you need a structural warranty

it has been usual for you or your architect to be told (mainly by warranty providers and private building inspectors) that you must have an insurance backed guarantee, IBG, for basement waterproofing. They allege, or claim, that it improves workmanship. It never has.

When I have asked them to clarify what they want the insurance for, they don't explain.

When I say that the only insurance is for the one thing that is not allowed by the Standard, internal drainage labour and materials, they remain silent.

Another favourite diversion by warranty providers and private building control bodies, is to try to claim that every word throughout BS8102:2022 applies to this project.

That has to be nonsense. Here is one reason why:

Your project is a new domestic basement yet to get the house on top.

BS 8102:2022 Protection of below ground structures against water ingress - Code of practice applies to all below ground structures.

If this web site is of interest, your project is not about a Victorian cellar conversion, or going under something already there, or commercial.

basement structural warranty

The Standard explains that a relevant path needs to be found through it. And the most obvious and appropriate, for a new domestic basement, is no leaks.

I had an IBG for my work guaranteeing absolutely no leaks in 2009. But then BS8102 changed to internal drainage and IBGs have only been for internal drainage labour and materials since. No insurance cover for leaks, flood damage, ill-health or clearing up.

I haven't found an insurer prepared to insure workmanship again yet, not least because I got too old to be insured myself.

But I have recently persuaded some building inspectors and warranty providers to drop this demand.

Internal Drainage Systems fail because the installers cover over all the leaks left by the contractor without fixing them first, the pumps can get blocked with mud and the basement flood. All in breach of Building Regulation C2 and BS 8102:2022.

When you get told you must have an insurance backed guarantee, IBG, immediately write a letter to or email that person. Put the conversation on record. Include or attach the letter from DLUHC and point out that if they want you to depart from BS8102:2022, by insisting upon internal drainage when Table 2 of the Standard does not want it in Grade 3 accommodation, then they are legally responsible for all the consequences, damages and costs.

Click on these two images to view and save the originals

Include in your letter, perhaps as enclosures, links or attachments, my web pages about the new laws and procedures, and perhaps this page as well.

You may have to write this to

The architect
The structural warranty provider
The building regulation control body

Explain, first of all, that as far as you have been able to find out, their insisting on an IBG means that they (architect/insurer/inspector) are insisting on a departure from BS8102:2022 known to fail and likely to incentivise or cause the leaving of leaks.

Leaks cannot all be identified and fixed until after the structure is completely weathertight, it has been cleaned and dried, and inspected before anything covers the basement inside. Because it fills up with rain and muck as soon as the wall formwork is put up.

Be in no doubt. If you have a quote from a CSSW that his company will paint or seal the concrete first, it excludes leaks. Leaks are very difficult to fix when water is coming in toward you, pushing your repair off before it sets and cures.

Mention that some leaks won't be identifiable when you complete your work and won't ever be identified if they insist they are covered over - unless and until the causes of flood damage and ill health are investigated.

Put it on record that if the basement leaks at any time in the future, that you will blame them. You will have their correspondence and lots of photos. You or the client will sue them, perhaps the Building Safety Regulator will prosecute them. And make it clear what is not covered by the IBG (only labour and materials are covered) and the client will win damages.

You are welcome to use my images in this letter or email.

I have a page about my efforts to bring about change here. This is where you will find who I persuaded to drop their demand for an IBG.

Prepare now. When anyone tells you to have an IBG, tell them that The Building Regulations, at C2, state that it is the walls, floors and roof that must be resistant to moisture. Allowing any part to fail, not be resistant to moisture, and expecting to pump water out is plainly not conforming with the Building Regulation.

If it were ever true they wouldn't have withdrawn and replaced BS8102:2009.

Structural Warranties, and how they take your money as well as make you re-insure them.

I quote several sources below.

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

Basement waterproofing would fall into this category. But it is unique in that it is excluded from the warranty cover.

Your newly built basement should not be covered over but 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.

Another client has since emailed to say that "BW: Build Warranty" have said the same.

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

This is Table 2 in BS8102:2022. I am going to compare it to Newton Waterproofing, for which you can get an insurance backed guarantee covering labour and materials only.

basement structural warranty

An architect emailed me the image below, saying: "Newton datasheet claims we can achieve Grade 3 to BS8102:2022 as below."

The architect highlighted the yellow. I underlined in pink and added beige highlighting.

basement structural warranty

The big question is, was the architect correct, or was the architect misled?

He highlighted in yellow, the following: "to achieve Grade 3"

But Table 3 states

No water ingress or damp areas^C) is acceptable.

Ventilation, dehumidification or air conditioning necessary; appropriate to the intended use^D), ^E).

I don't think that the Standard allows Grade 3 to be achieved with ventilation, dehumidification or air conditioning. I think it is only saying that, where appropriate, have those things after "No water ingress or damp areas" is achieved.

I don't think that if the pumps block with mud and the basement floods, that any amount of ventilation, dehumidification or air conditioning will avoid mould, ill health, the building regulation not complied with, the law broken, and the developer prosecuted.

Newton are deliberately mis-leading. I wrote to them saying I think they are liars.

Highlighted in beige, they claim waterproofing cannot achieve Grade 3.

In my opinion, they mean that Newton waterproofing cannot achieve Grade 3.

Type A barrier protection is not a valid waterproofing defence in BS8102:2022 because it does not stick everywhere and it gets damaged by following on site operations, but not repaired.

Yet their words are, that the success is dependent upon the barrier working.

You will read in the letter from DLUHC, that deviating from the British Standard requires proof that the building regulation will not be failed.

Yet Newton rely entirely on the workmanship of others not damaging the barrier they installed. Then the pumps never all being blocked by mud.

All of it out of their control.

The truth.

Supervised waterproof concrete meets Grade 3 of BS8102:2022, if I am the supervisor.

Has done for over 100 basements for over 10 years.

No one can damage concrete later.

Leaks through concrete joints and cracks are easily fixed.

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.

Back to the Basement Building Questions Answered menu.

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For a fixed fee of £199 I will answer all your questions by email. More details here.

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