13k sqft self build in Hertfordshire

[Iceverge]

The more I look at it the more I think the comment above about it just being "a design to secure planning permission" makes more and more sense. 

 

Its baffling how the designer expected the roof over the kitchen to stay up. If it is concrete it could weigh 250 tonnes and yet seems to be supported only at the end and them in turn partially below by fresh air.

 

There is some artistic licence with the sketches too and they seemed to have moved it to the southern hemispheres with some of the sketches looking at the shadows. This makes it all look much sunnier and more inviting that a Northern Elevation is in reality in our neck of the woods. 

 

 

 

 

 

 

 

 

Edited October 29 by Iceverge

[LadybuilderLOL]

12 hours ago, Conor said:

Hi. We built a three story ICF house with basement, but not on this scale.

 

 

(I'm a civil / environmental engineer, not structural, I'm sure our resident expert will comment in due course)

 

With the scale and design of this structure you might beyond the realms of normal building methods, and builders for sure. The best construction method will be determined largely by the structural requirements. Your basement walls will likely have to be shattered reinforced concrete as ICF blocks aren't ideal and most won't be wide enough, you are looking at 400mm+ thick walls here. I'm sure there are ICF projects similar to scale, you'd need to dig in to it. Same for you floor decks. These will be commercial building / car park type affairs at ~250mm thick with a bit of chunky steel holding them up. These kind of things, plus the excavation requirements, massively change the game, and costs. There is little economy of scale when you jump from a residential brick n block to a pseudonym commercial type construction. 

 

Not going to comment too much on the design, but things like you have an unfeasible amount of glass (apart from being uncomfortable, unlikely you'll pass SAP assessment), and cars are waterproof and don't mind the cold

 

Cost wise, you say you are prepared, I'm assuming you know this will cost about £4m? It's never too late to change a design. A full redesign could cost you less than 5% of the construction cost, but could save you 30% or more.

 

I'd speak to an SE before you go anywhere, and another look at the design. You could shave off a £million and not lose any rooms /functionality for sure.

 Thank you so much for your comments. We definitely don't need a 10 car basement- by the time we finish building the house we won't have any money left to fill it with any cars 😅I have been recommended to consult with a SE today and that is my next stop. Yes you are right the SE they used in this design normally builds bridges and car parks... I haven't paid for the drawings because Im not sure we are going to build it to their design. I'll be back with further updates! Try to track down the already completed GIR or organise a new one 1st. 

[LadybuilderLOL]

Hey guys- I'm very overwhelmed by all the comments. 
Thank you all for contributing and I try to respond to all in some form here or quoted...please bare with me
 

in the short- I should tell you- we have already submitted a pre app (3 weeks ago) for a smaller dwelling of just under 7000sq ft. It does not have a basement. 
 

we have 4 kids so we definitely won't be living on site...although I have managed to rent the bungalow on a company let so it's not a sitting duck they moved in on Monday. 
 

the muck away issue was solved by the previous owner on the land behind the plot- there is 10acres behind the bungalow and 3 in front. No shortage of space.

yes we already have planning granted and the groundwork's were already commenced. 
our options will be to submit a variation of the current plans and make the house smaller- if this can be done, or go in for a new planning application for a different designed house safe in the knowledge that a precedent has already been set. I was reluctant to submit new plans because I want it done already! 
 

 

 

 

Edited October 29 by LadybuilderLOL

[LadybuilderLOL]

22 hours ago, Thorfun said:

Wow! That’s one heck of an ambitious project and a stunning design. I wish you all the best with it. 
 

looks like most of the building is built into the landscape so concrete really is the only way. The above ground bit could be timber frame if you wanted a change of materials. 
 

prefab concrete panels will be quick but expensive. Formwork and pouring concrete surrounded by EPS would be cheapest I imagine but will take longer. ICF might be comparable but you’d need to get quotes and SE drawings that are ICF specific afaik. 
 

checkout the basement forum as that’s pretty much what you’re building. There are many ways to do it and it all depends on what works for you and your budget. 

Thank you- I have really enjoyed reading your blog posts this morning- you have probably noticed 😂😂

I have spoken with a few ICF contractors this week who are confident they could build design or work with me to alter it. I have no firms decisions and I'm still trying to formulate a plan and navigate. We have submitted a pre app- and await the response from the planners and will take it from there. 

[LadybuilderLOL]

22 hours ago, JohnMo said:

Nice looking place but not convinced by a number of things that seem strange.

 

Loads of bedrooms (2 floors worth) and limited living space in comparison. Not all those people housed in the bedrooms should want to crouch up on a couple of sofas.

 

But sorry that size build everything will all be astronomical. 1200m² is just huge it's 6x bigger than our very roomy 3 bed house.

 

Hope you proof read and facts everything, so you don't make yourself look a foolish. Chat bots make a good looking document that may or not be factually correct.

I am not self reliant on chat gpt just really like for it to take the guess work out sometimes 😂😂

Your comments are valid. The house is way too big... 

 

[LadybuilderLOL]

11 hours ago, Kelvin said:

Why is it so big? Do you really need so many bedrooms? You could half the size (which would still be enormous) with a similar design. There’s a £2 million saving. Unless you really need a commercial sized building I’d seriously rethink the design especially as you are already baulking at some early estimates. 

The estimate was provided by the seller, It doesn't make sense not to explore all options, we bought the understanding the costs. 
I agree about the size. I have 4 kids and I want a simple life (😅).

 

I have some site experience and it has always been my dream to self build- I could outsource to a PM but where's the fun in that- although I do have great assistance- which I will share with this community later down the line.
We need a minimum of 6 bedrooms because we have 4 kids. 

[LadybuilderLOL]

3 hours ago, twice round the block said:

Great plot 

Bad design. 

 

I would hire in another architect and do a design that works for your family. 

 

Art Deco on the side of a hill could look spectacular.

You may go through a couple of architects until you get one that really understands what is needed on the site that fit's your, "must have list and it would be nice if"

 

Unfortunately some architects just don't get it and see it.

There are plenty of good ones to choose from in the area that are RIBA affiliated.

Even when you get one that works with you; you may have too reign them back in as they can get carried away.

 

We really like the house design in lots of places but it doesn't work for our family and has a 5000sqft car park- which we really don't need. So redesign or new design we are unsure yet of which way to go. 
 

we may build it as it's designed if we find the right contractor as we could start very soon- but it's very unlikely especially after reading all your very valuable comments. 
 

 

[LadybuilderLOL]

13 hours ago, Conor said:

Hi. We built a three story ICF house with basement, but not on this scale.

 

 

(I'm a civil / environmental engineer, not structural, I'm sure our resident expert will comment in due course)

 

With the scale and design of this structure you might beyond the realms of normal building methods, and builders for sure. The best construction method will be determined largely by the structural requirements. Your basement walls will likely have to be shattered reinforced concrete as ICF blocks aren't ideal and most won't be wide enough, you are looking at 400mm+ thick walls here. I'm sure there are ICF projects similar to scale, you'd need to dig in to it. Same for you floor decks. These will be commercial building / car park type affairs at ~250mm thick with a bit of chunky steel holding them up. These kind of things, plus the excavation requirements, massively change the game, and costs. There is little economy of scale when you jump from a residential brick n block to a pseudonym commercial type construction. 

 

Not going to comment too much on the design, but things like you have an unfeasible amount of glass (apart from being uncomfortable, unlikely you'll pass SAP assessment), and cars are waterproof and don't mind the cold

 

Cost wise, you say you are prepared, I'm assuming you know this will cost about £4m? It's never too late to change a design. A full redesign could cost you less than 5% of the construction cost, but could save you 30% or more.

 

I'd speak to an SE before you go anywhere, and another look at the design. You could shave off a £million and not lose any rooms /functionality for sure.

Hi Conor, yes we are aware of the costs. I look forward to reading your comments throughout this forum and learning from your experiences. I appreciate your input. I have responded to some of your comments below. 

[LadybuilderLOL]

2 hours ago, Indy said:

The initial post indicates that it already has planning so I'm sure these things would have been considered already?

Yes planning has been granted and we have a cert of law dev. 

[LadybuilderLOL]

3 hours ago, saveasteading said:

And a legal requirement. I'm rather shocked that the architect (A?) doesn't know this.

My husband has been complaining about who will take the bins out 😆 

[LadybuilderLOL]

3 hours ago, twice round the block said:

Great plot 

Bad design. 

 

I would hire in another architect and do a design that works for your family. 

 

Art Deco on the side of a hill could look spectacular.

You may go through a couple of architects until you get one that really understands what is needed on the site that fit's your, "must have list and it would be nice if"

 

Unfortunately some architects just don't get it and see it.

There are plenty of good ones to choose from in the area that are RIBA affiliated.

Even when you get one that works with you; you may have too reign them back in as they can get carried away.

 

We have hired a different architect and have submitted a pre app. Nothing is set in stone at this moment in time. 

[LadybuilderLOL]

22 hours ago, JohnMo said:

Nice looking place but not convinced by a number of things that seem strange.

 

Loads of bedrooms (2 floors worth) and limited living space in comparison. Not all those people housed in the bedrooms should want to crouch up on a couple of sofas.

 

But sorry that size build everything will all be astronomical. 1200m² is just huge it's 6x bigger than our very roomy 3 bed house.

 

Hope you proof read and facts everything, so you don't make yourself look a foolish. Chat bots make a good looking document that may or not be factually correct.

My mistake I added the original drawing and then the variation drawing. 
it is 3 floors. 
basement/ car park, mainly bedroom 1st floor and then 2nd floor living area. 
I will post some video and pictures of the actual land.

i haven't been able to successfully capture the whole plot in pictures or video yet. 

[LadybuilderLOL]

11 hours ago, Indy said:

This looks fantastic and I'm going to go the opposite direction and say why not build the space if you can afford to. Whether you need 13k+ sq feet is debatable but I'm all for space. 

 

The other points already raised also ring true - if you can afford to build a house of this house, then its unlikely you'll be living in a static caravan for 2 years especially with kids in tow. 

 

Also, I would want a specialist concrete builder doing the E2E project management on this rather than risk taking parts of it on yourself. Sounds like a lot of structural elements to consider and be done right. 

 

Following the thread with interest. 

Hey 👋🏻

thank you. Your response are my husbands thoughts: but I'm the one that will be maintaining the house not him lol. 
 

I will be handing the superstructure to a main contractor for certain. 

[LadybuilderLOL]

5 hours ago, miike said:

What is the sqm of the actual living areas? Looks to me like <50% of the 13k sqft is actual living space, with the rest as garages/courtyards/terraces. If I'm correct, then I think it could be built for a lot less than some of the above estimates. 

 

I recently built a not entirely dissimilar 3 storey house on a sloped site with 500m2 internal space + ~200m2 of terraces. The semi-submerged basement used two skins of blockwork, with a concrete filled cavity. The upper two floors were built with brick/block. There's about 75 structural steel beams. 

 

I would suggest looking at this method of construction rather than other more specialist types. I'd then approach groundworks companies and only provide limited drawings and ask to quote for specific sections - eg. the excavation, slab and blockwork for the basement floor. If you send all these drawings over then you'll probably get 50% added on to the price as they'll assume you can afford it based on the design.

 

Excluding windows, I'd expect c£1m for building the shell of this house. You should budget for a lift though if you're going to have parking on the basement floor and the kitchen two floors above - it's quite a journey when bringing in grocery shopping. 

 

 

There is a very  unnecessary 5000 sqft car park 🙃

 

thank you for your input 🤗

I'll be back with progress updates. 

[Gus Potter]

On 28/10/2024 at 20:34, LadybuilderLOL said:

Hey guys

Hiya and thanks for posting on BH.

 

I've had a quick look at what you propose. With my SE hat on.. because it it so big you probably have loads of stiff structural floors / roof deck.. unless there is a massive atrium. This can be an economic form of construction.

 

The size tends to lean towards standard commercial building construction.. nothing new and you should get competetive prices for a project of this scale.. it's basically office construction that is fitted out as a house with enhanced U values, heating / cooling systems etc.

 

Looks great to me! Keep posting.

[saveasteading]

6 hours ago, Indy said:

has planning so I'm sure these things would have been considered already?

Not the planners' role. The designer's.

I'm thinking the design isn't by a building expert.

 Later, building control would refuse approval

[SteamyTea]

23 hours ago, LadybuilderLOL said:

yes we already have planning granted and the groundwork's were already commenced. 

I hope you have your CIL exemption in place (if it is needed in your area).

[LadybuilderLOL]

11 hours ago, SteamyTea said:

I hope you have your CIL exemption in place (if it is needed in your area).

We are exempt. 

[SteamyTea]

49 minutes ago, LadybuilderLOL said:

We are exempt

Saved a few quid already.

[Firsttimer]

Very exciting. I'd initially budget at the very least £3k a metre squared and not allowing for any spendy finishes. This doesn't include fees. It might be worth getting an engineer engaged at the planning stage given a lot of the wall will be retaining.

Edited 5 hours ago by Firsttimer