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New build with basement Essex/London boarder


Hyside

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On 04/11/2020 at 17:41, Jilly said:

its detached, you don't need to worry about party wall agreements, that's only if you are doing something to a shared structural wall, as far as I know, unless you mean something to do with the basement?

You need to be careful here . We are detached , but digging out a big hole puts the fear of God into your neighbors- no matter how near/far they are to your build . Although I arranged for the dig I still had to take out special I.e expensive insurance ,against any issues as its dug i.e neighbors house collapsing - because that’s likely to happen right ?

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@Thorfun Really can't disagree with any of the points you've made there. They were recommended - but seemed to have limited experience with basements. If I went to another one with experience with ICF/basements do you think they would be able to use the calcs from my SE and just design the basement or would they have to start from scratch again?

 

@pocster Thanks for the reply - I had thought about that to cover myself. Could you give me an idea on cost for that and who you used please. Ta

 

Thanks for all the replies - Very much appreciated. Owe you all a beer.?

 

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2 minutes ago, Hyside said:

@Thorfun Really can't disagree with any of the points you've made there. They were recommended - but seemed to have limited experience with basements. If I went to another one with experience with ICF/basements do you think they would be able to use the calcs from my SE and just design the basement or would they have to start from scratch again?

 

@pocster Thanks for the reply - I had thought about that to cover myself. Could you give me an idea on cost for that and who you used please. Ta

 

Thanks for all the replies - Very much appreciated. Owe you all a beer.?

 

Sure - let me dig that up - it was a while ago ...

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13 minutes ago, Hyside said:

 Really can't disagree with any of the points you've made there. They were recommended - but seemed to have limited experience with basements. If I went to another one with experience with ICF/basements do you think they would be able to use the calcs from my SE and just design the basement or would they have to start from scratch again?

can't answer that sorry. your best bet is to speak to some SEs and see what they say. 

 

good luck!

 

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I have done a basement in ICF.  We used Polarwall.  You need to make sure your warranty company is OK with it.  You must use type C internal drained cavity membrane and pump, as it is not possible to guarantee that the concrete is contiguous in the forms.

 

The reinforcing and concrete thicknesses is the same as if you did normal shuttered RC walls.  We used Easi Joist floor above and this was treated as "partially propped" for the structural calcs.  We did timber frame above.  The basement was the same footprint as the floors above plus a light well.

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Another ICF basement here. Integraspec ICF + Kryton waterproof concrete.

 

We focused on the primary structure for waterproofing, there are no secondary internal or external membranes, pumps etc.

 

This is a BBA (I might have the wrong approval agency, going from memory) approved scheme and our insurance had no issues with it. The ICF provider were involved in the design, build, sign off and issued a warranty.

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for me the ICF quotes were stupid money (had 2 from Nudura installers) for the basement. I'll be getting quotes from ground workers doing in-situ RC to compare and if those come in at the same price as the ICF then I'll be knocking the basement on the head as we wouldn't be able to afford it. I'm hoping the in-situ will be cheaper as I'd really love the basement!

 

only time will tell....

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9 minutes ago, Thorfun said:

for me the ICF quotes were stupid money (had 2 from Nudura installers) for the basement. I'll be getting quotes from ground workers doing in-situ RC to compare and if those come in at the same price as the ICF then I'll be knocking the basement on the head as we wouldn't be able to afford it. I'm hoping the in-situ will be cheaper as I'd really love the basement!

 

only time will tell....

Do it yourself ! Man up ?????

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2 minutes ago, pocster said:

Do it yourself ! Man up ?????

I have considered it to be fair. buy myself a 12-ton digger and figure it all out as I go along.

 

but then I'd end up building the house for myself as the wife would probably leave me coz the house will never get finished.

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25 minutes ago, Thorfun said:

I have considered it to be fair. buy myself a 12-ton digger and figure it all out as I go along.

 

but then I'd end up building the house for myself as the wife would probably leave me coz the house will never get finished.

Welcome to my world ! Though SWMBO hasn’t left yet 

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3 minutes ago, Thorfun said:

errr....didn't you just say....

 

 

?

Yeah - I meant get a guy to dig the hole unless you do have a digger handy - then build the rest . I got a guy with a 40 ton digger - not something I really want to do 

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Just now, pocster said:

Yeah - I meant get a guy to dig the hole unless you do have a digger handy - then build the rest . I got a guy with a 40 ton digger - not something I really want yo do 

yeah I know. was just being facetious. sorry.

 

it is definitely a possible consideration once I've weighed everything up.

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18 hours ago, pocster said:

Sure - let me dig that up - it was a while ago ...

@Hyside

 

I think it was JCT 21.2.1 insurance. It was about 1K about 6 years ago. Only was valid I think for about 6 weeks. So allows for the dig out and then any 'issues' afterwards.

It helped quell neighbours minds. I think from memory if there had been a problem at any property the excess was something like 12k per property!!!!!!!

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On 07/11/2020 at 16:01, Hyside said:

@Thorfun Really can't disagree with any of the points you've made there. They were recommended - but seemed to have limited experience with basements. If I went to another one with experience with ICF/basements do you think they would be able to use the calcs from my SE and just design the basement or would they have to start from scratch again?

 

@pocster Thanks for the reply - I had thought about that to cover myself. Could you give me an idea on cost for that and who you used please. Ta

 

Thanks for all the replies - Very much appreciated. Owe you all a beer.?

 

 

We used two SEs, one was part of the timber frame package so we did not interact with him directly. Second was commissioned by us and used the spec of the TF above (point loading etc) and the output of the GI to design the basement.

 

It was a full structural design with steel schedules etc that we were able to take to contractors for quotes.

 

The practice I used also specialise in ICF, believe they are now called Build Collective in Bristol.

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On 07/11/2020 at 17:18, ragg987 said:

Another ICF basement here. Integraspec ICF + Kryton waterproof concrete.

 

We focused on the primary structure for waterproofing, there are no secondary internal or external membranes, pumps etc.

 

This is a BBA (I might have the wrong approval agency, going from memory) approved scheme and our insurance had no issues with it. The ICF provider were involved in the design, build, sign off and issued a warranty.

 

We used shuttered concrete and SIKA waterproofing (no membranes inside or out), also warrantied. This is the key bit, irrespective of the system, if there's an insurance backed warranty then you can sleep easy.

 

 

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9 minutes ago, Bitpipe said:

The practice I used also specialise in ICF, believe they are now called Build Collective in Bristol.

I got a quote from them and they were very expensive. the most expensive of the 4 quotes I received by far. I'm sure they'd do a great job but at that price I couldn't justify it.

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  • 1 month later...
On 07/11/2020 at 13:05, Thorfun said:

 

this just seems wrong to me! the SE needs to calculate the load on the walls of the basement etc to make sure it can take the load of the house and hold back the earth around it. so it really should be the structural engineer who designs the basement. I understand getting a waterproofing expert as per BS 8102:2009 involved to design the waterproofing but it really should be the SE who designs the basement.

 

when I sent my plans to SEs for quotes the basement was on it and I made sure that the basement design was included in their remit of work and costs. I'm really surprised by the response of yours.

 

but that's just my opinion and hopefully someone who knows what they're talking about will be along soon.

Hey Guys,

 

I am just going through this now for my own project. We are planning a full footprint basement. My SE is in the process of providing the basement design, which will basically include basement and wall spec. My SI is complete and we have water at 1.5m so planning to dig trial pits once the house has been demolished to get a better idea on water levels. For waterproofing, I am not expecting my SE to provide this. Instead, I have liaised with Sika for concrete waterproofing, and they have referred me to CSSW approved tanking specialists. This approach will ensure the installation meets all warranty and build regulations. I looked at ICF, but it does not seem to be as good as in-situ cast concrete using formwork.

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1 hour ago, Internet Know How said:

they have referred me to CSSW approved tanking specialists

our architects referred us to an approved waterproofing specialist who will install the type C waterproofing and guarantee it for 10 years and quite a reasonable cost as far as I'm concerned. for me that warranty is worth it's weight in gold. I could do it myself but I'd be cacking my pants every time it rained.

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On 02/01/2021 at 19:44, Internet Know How said:

Hi, I am interested what the sump and pump was used for? Is this for taking foul back up to ground level or are you constantly pumping external water out because you are building in the water table? 

 

We didn't need one in the end but my understanding is that it is primarily to remove the continual ingress of ground water, however I believe it can also be used for internal fouls also (if you had wet services in the basement).

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On 02/01/2021 at 19:57, Internet Know How said:

Hey Guys,

 

I am just going through this now for my own project. We are planning a full footprint basement. My SE is in the process of providing the basement design, which will basically include basement and wall spec. My SI is complete and we have water at 1.5m so planning to dig trial pits once the house has been demolished to get a better idea on water levels. For waterproofing, I am not expecting my SE to provide this. Instead, I have liaised with Sika for concrete waterproofing, and they have referred me to CSSW approved tanking specialists. This approach will ensure the installation meets all warranty and build regulations. I looked at ICF, but it does not seem to be as good as in-situ cast concrete using formwork.

 

Our contractor used Sika and they came to site a few times to inspect installation of their system (water bar etc) and issued the warranty.

 

The only issue with ICF is that you can't see the final quality of the concrete in the same way you can when you strike in-situ formwork. If the mix is the correct spec and is poured and vibed properly during the pour then all should be well. 

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