Basement Structural Warranty.

Basement Structural Warranty and Basement Waterproofing Insurance Backed Guarantee

Not to be confused with my guarantee, contractor guarantees, or product certification. They are dealt with on another page. Link opens in a new tab.

This page explains

What to expect, and what you shouldn't expect, from a Structural Warranty.

What to expect, and what you shouldn't expect, from an Insurance Backed Guarantee. IBG.

And why, if you must have a structural warranty, you might do best only approaching Protek.

Protek appreciates that they don't insure beneath ground waterproofing so they don't require re-insurance for what they don't insure.

Your mortgage provider doesn't pretend to be a building expert. They insist upon a Structural Warranty so that your property is inspected by people who are.

Your Structural Warranty provider is an insurance company.

Many inspectors will tell you that they insist upon an IBG because it improves workmanship. That might be true for windows. But, as I explain below, leaks aren't caused by the workers installing internal drainage. Those workers are the people who ignore and cover over leaks already there so that no one else sees them.

If basement waterproofing needs an IBG, it should be to guarantee against leaks. But it doesn't because the laws are in place to ensure that your building regulation inspector has inspected and confirmed Building Regulation C2 is complied with.

But I have never known building control to make such a visit.

Your architect, as your Principle Designer, has a new legal duty to ensure that all workmanship is proven to have been carried out well. This is far from complied with if your architect specifies all leaks to be covered over.

Neither a structural warranty nor an insurance backed guarantee have any legal weight. You want them only to get your mortgage or to sell your property to someone else who will need a mortgage.

The law is mostly summed up in these 5 points.

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. 3.16 does not replace Table 2.

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. The client should choose very carefully.

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.

Please be in no doubt. The insistence by the structural warranty provider on an insurance backed guarantee for an internal drainage system (IDS) in a new basement structure yet to be built has been the cause of floods and breaches of Building Regulation C2.

Laws changed very recently. The British Standard changed recently. If you are yet to have a basement built and you have internal drainage, you are likely to have a flood, mould, illness, and face prosecution. You have no defence because you did not build to the approved British Standard.

An internal drainage system is designed to pump out water that leaks into a basement.

But only water.

If you get a quote, it will insist (a) that you have two pumps, at least, and (b) that you also have a maintenance contract to remove mud periodically.

Why should there be mud?

Because the contractor having to dig extra deep and install the sump before they continue building any of the structure knows that if they cut costs and let water leak in it will be pumped out.

But over the years since 2009 when the IBG for IDS became normal, contractors learned that if they leave more leaks and worse leaks they still get paid the same.

But as worse and more leaks were left so more mud got in during particularly wet weather.

And once a pump is blocked by mud it doesn't pump the water out any more.

And if the storm continues, the basement floods.

There is mould. Illness. The law broken.

What of the Insurance Backed Guarantee?

It covers labour and materials for the sump, the pump, the drainage channel, and the drainage membrane over the walls and floor only.

The Insurer says nothing to do with us.

What of the Structural Warranty?

They all exclude beneath ground waterproofing.

Their insurer also says nothing to do with us.

So, what should you do?

Insist that the new Building Safety Act 2022 is complied with.

Insist that the Approved Document BS8102:2022 is complied with.

Choose a warranty provider that agrees that since it's cover excludes beneath ground waterproofing they have no interest in it.

Make sure that your architect clearly understands they must comply with Principle Designer's duties. Just two of which are :
- work with the principal contractor and share information about ... monitoring ... building work
- Principal designers ... pass on necessary information to contractors and explain to them how to demonstrate that elements are built properly.

"No Leaks" needs to be considered with the two points under item 4.

Monitoring and Demonstrating Built Properly must now be seen as unavoidable legal duties by everyone with a part to play to ensure no leaks or damp patches.

Inspections.

Inspections need not be by the architect themselves. They can delegate with a sound and proper agreement in place.

My best advice is constant supervision during the important processes. Particularly design, concrete blinding, steel reinforcement, formwork, joints, and concreting.

It amazes me how often experienced labour get concrete blinding really badly wrong. Yet it is the simplest task of all. Anything wrong costs and wastes money.

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 or damp patches.

When you get told you must have an insurance backed guarantee, IBG, immediately write a letter or email to 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 and 3.16 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 and attach them to your email

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 later 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 IDS labour and materials are covered with nothing for the structure) and the client will win damages.

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

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.

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

Back in 2009, the inspector's requirements were

The roof and windows are fully weathertight

The basement cleared of debris, cleaned and dried

The basement inspected by him for leaks after a period of heavy rain

The basement passed by him as dry.

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 pay for their re-insurance.

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

STOP PRESS. PROTEK.

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."

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

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.

This is Table 2 in BS8102:2022. I am going to compare it to Newton Waterproofing (as sent to me by an architect during February 2024), for which you can get an insurance backed guarantee covering labour and materials only.

basement structural warranty

The 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 two years ago on March 31st 2022 and replaced by an entirely different approach to basement waterproofing: BS 8102:2022.

Back to the Basement Building Questions Answered menu.

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