Registered basement company required to construct basement for warranty????

[Wuey]

Hi there

 

Looking for some clarity please, about what we've recently been told by our architect. To be honest, i'm not entirely clear on the whole issue so I may not even be asking the right questions, but here goes....

 

We recently amended our plans (and got approval) to add a basement to our new build.  We're going to use ICF to build the house and intended to also use ICF for the basement.  At a recent meeting with our architect he told us that in order to get a warranty for the build, the basement should be done by a registered basement company and not suing ICF, as the regulations changed in April (and he explained to us the need for a minimum of two forms of waterproofing etc).

This was news to us, and whilst we're happy to build the basement with something other than ICF if that makes life simpler, e.g concrete form etc, I'm a bit cynical about the need to use a 'registered basement company' as this just sounds like its going to get very expensive. So my questions are;

 

1. Is this correct about needing to use a registered basement company, or can a good Groundworks company or builder do the basement? Or what would those of you who've been down this route already recommend if there are other options we should be looking at?

2. From a warranty perspective what happens if we don't use a registered basement co, i.e. are we mad to even consider not using one?  Would we not be able to get a warranty at all for any of the new build then?

3. Does our basement construction choice also potentially have a negative impact on a mortgage further down the line if we needed to remortgage?

 

I don't know, what I don't know, so would really appreciate some help!

 

Thanks in advance

 

 

 

[Mr Punter]

ICF in a basement can be tricky as you cannot inspect the concrete.

 

A groundworks company should be able to build a basement and they do not need to be registered.

 

You will probably still need to use 2 forms of waterproofing.

 

Basements are fairly high risk as the waterproofing can often fail and the cost to remedy can be high.

 

You need a ground investigation and structural engineer.

[Temp]

Have you got a warranty company arranged? Check their terms an conditions.

[Wuey]

Thanks for the replies.

 

[Big Jimbo]

I dont believe that any of the warrenty providers provide cover for basements. However, i'm happy to be proved wrong. If they don't then i would expect potential problems with trying to obtain a mortgage in the future.

[Conor]

No, you just need a warrantied waterproofing system. We used an external bitimous membrane system. They came out, supervised the start, inspected the final works. Mortgage lenders and insurers care more about water I guess than anything else.

Edited July 6, 2022 by Conor

[Selfbuilder786]

Hi would you have a contact number for them. I rang up https://ikogroup.co.uk/contact-iko/ who informed me that their primer is solvent based and don't have no product for icf

[Bitpipe]

We got a warranty for our build, including basement, with just one waterproofing system. We used Sika waterproofing (concrete, seals, bungs etc) which itself was warrantied but they had specific build process to follow which was documented and inspected.

 

Our structural engineer, who designed the basement, decided that WPC was sufficient based on the comprehensive GI reports they commissioned.

 

As said above, ICF is a risk only because you can’t see the finished pour quality but there’s nothing inherently wrong with it. We did traditional shuttering with a TF on top. However it may not be acceptable by your warrantied WPC vendor (e.g. Sika).
 

I’d listen more to your SE than architect on this - get a very good understanding of your ground conditions, get SE to spec waterproofing that addresses those conditions and press on.

 

Even if everyone is ok with waterproofing concrete you may want to add an external membrane if you can absorb the cost but steer clear of internal membrane, sump & pump etc as that is a lot more complicated - usually  relied upon for retro fit basement where leaks are assumed.

[Wuey]

Thank you everyone for your replies, much appreciated😊