Garage/Car Port Conversion to Annex

[livingthedream]

Hi All, So embarking on a project, where we are buying a new house which currently has a nicely built car port, built in single concrete block wall, covered in oak cladding to match the house, so there are two major parts I could do with some guidance on. So in general the whole structure will be single layered concrete block, external covered with Oak cladding, internally we are putting in a fully insulated stud walling, and floating floor.

 

1. We are extending the carport out to create a lounge area of 4.5m X 4m single storey, flat roof, with a french doors and a window being installed, what I am getting confused is, what base do I need and roughly what depth,  in absolute basics, I thought it would be a case of just excavating out to what ever depth needed, and fill it with poured concrete, or is that approach just to simple

 

From there the single concrete block would be built on, and the internal floating floor would just run through to the already concrete floor of the car port etc 

 

But I can't seem to find any guidance on what sort of footing or base options I would need, I've read about foundations etc being 1m deep etc, then I read options of 250mm deep with sub base, concrete poured etc, any advise would be great.

 

2. Water incoming and waste - If someone can tell me if I am complete wrong in my thinking. The car port is away from the main house, and assuming the main sewer is somewhere at the front, it's a fiar way away, so the idea I had was, at the back of the house there is a utility room, can I trench a cold water feed and a grey waste pipe to this room and then use a macerator type setup to take the en-suite and kitchenette waste back to the house?? and can both these run within the same trench.

[ProDave]

New build house with a car port detached from the house that you want to turn into a self contained annex?

 

Have you considered:

Covenants or restrictions imposed by the developer?

Planning permission?

Building regulations?

 

Those are required in sequence, and the latter, building regulations will tell you how to build it, if you get that far.

[livingthedream]

Thanks for the response,

 

Covenants or restrictions imposed by the developer?

 

This is a single house in the middle of no where, not a development estate. Similar property up the road has just gone through same process of converting garage port to annex

 

Planning permission?

 

Permitted development, falls under outbuilding and incidental use. 

 

Building regulations

 

Building regs will be followed, just need to get budgets in place to understand best direction of the above

[Olf]

1 hour ago, livingthedream said:

can I trench a cold water feed and a grey waste pipe to this room and then use a macerator type setup to take the en-suite and kitchenette waste back to the house??

 

32 minutes ago, livingthedream said:

Permitted development, falls under outbuilding and incidental use. 

 

If it's got water, it is not incidental use. 

 

1 hour ago, livingthedream said:

But I can't seem to find any guidance on what sort of footing or base options I would need

Dig a hole, check what used for the existing carport, match it

[livingthedream]

2 minutes ago, Olf said:

 

If it's got water, it is not incidental use. 

 

Understood if it's for a direct member of family to reside, then it's seen as an extension to the house, and therefore under permitted development, only if we were going to rent it out, or airbnb it etc, is it classed as separate

[ProDave]

37 minutes ago, livingthedream said:

 

Understood if it's for a direct member of family to reside, then it's seen as an extension to the house, and therefore under permitted development, only if we were going to rent it out, or airbnb it etc, is it classed as separate

It's more complicated than that.  Any occupant is expected to use some of the facilities in the main house, e.g. perhaps the kitchen, or even the bathroom.  If it is fully self contained and has it's own kitchen and bathroom so they live completely independent, than it fails the "incidental" test.

[livingthedream]

1 hour ago, ProDave said:

It's more complicated than that.  Any occupant is expected to use some of the facilities in the main house, e.g. perhaps the kitchen, or even the bathroom.  If it is fully self contained and has it's own kitchen and bathroom so they live completely independent, than it fails the "incidental" test.

 

I am going through the planning portal to get advise anyway, so really was just asking the questions above on direction of the project, rather than a debate about planning permission

[Mr Punter]

An existing and proposed plan may be useful.

 

For foundation depth you can normally just do as per the current house.

 

I really dislike macerators and if there is any way you can achieve gravity drainage then do that.

 

There is no issue with water and drainage in the same trench.  Water will normally be at the bottom, at least 700mm below ground.

[livingthedream]

2 minutes ago, Mr Punter said:

An existing and proposed plan may be useful.

 

For foundation depth you can normally just do as per the current house.

 

I really dislike macerators and if there is any way you can achieve gravity drainage then do that.

 

There is no issue with water and drainage in the same trench.  Water will normally be at the bottom, at least 700mm below ground.

 

Thanks Mr Punter, yes I am getting plans finalised.

 

Current house, of the current car port concrete flooring?

 

I agree on the Macerator route, it was really as I understand, we can join up through the grey waste of the utility which is closer than trying get gravity drainage to the sewer, I am awaiting confirmation on sewer location, if it's down the end of the drive, then it's a straight, albeit long run