Just went through numerous posts on static caravans and other building that are used as an accommodation during the build. Could not find a matching case though. 

 

Most people said we'd need to move out for quite a while during the extension build. We have quite a bit of space in the rear garden so could easily build a large enough structure which would eventually be used as a gym. My question is "is this legal", i.e. do we need the dreaded planning for it. We are not in AONB and I know generally PP would not be required for a gym, but then we can't live there with kids, can we?

My understanding is as this is an extension we would continue paying council tax for the main house. 

Is the "Gym" covered under permitted development?

 

If so build it now before you start the work on the house.  Then when you apply for planning for the extension, include in that, temporary habitational use of the "gym" for the duration of the building work.

 

As discussed on another thread, if all the occupants of the gym are working on the build then you don't even need planning permission to use that, as temporary workers accommodation is permitted development anyway.

 

We had a slightly related unusual situation that we want to keep the static caravan as a studio, workshop and store room, i.e as a garden outbuilding.  I deliberately placed it where it would fall under the permitted development rules as a garden building, but of course PD does not come into effect until the house is complete.

 

So when I did the planning application for the house, I asked for permanent permission for the caravan.  Initially the planners said no, but when I pointed out to them that on the day of completion, I could remove the caravan, and them immediately replace it with an identical caravan in an identical location as a permitted development garden building, they agreed and changed it to "habitational use of the caravan shall cease upon occupation of the house"

 

 

Thank you, Dave

 

The garden room/gym would be a permitted development AFAIK. But we already have PP for the extension via an appeal hence I am not particularly keen on talking to planners again. The "temporary habitation" wouldn't pass as a non-material amendment (after being built), would it? 

And as we have kids we can't claim we are all going to be working on the build. 

Have you sketched an accommodation plan for your temporary accommodation? I ask because a family of 4 will struggle in less than 400 sq ft through a winter, which is large gym in the back garden.

6 minutes ago, epsilonGreedy said:

Have you sketched an accommodation plan for your temporary accommodation? I ask because a family of 4 will struggle in less than 400 sq ft through a winter, which is large gym in the back garden.

This family of 3 survived a Highland winder in a 280 square foot static caravan.

5 minutes ago, ProDave said:

This family of 3 survived a Highland winder in a 280 square foot static caravan.

 

 

I took a standard width and full length static caravan as the basis for my comparison which came out at 418 sq ft. Swmbo and I are finding life for two in an extra wide static with 451 sq ft too comfortable = lower motivation to crack on with the self build.

 

As the OP is free of the road haulage constraints of a static there is an option to be more creative with the space for example in a recent TV example bedrooms were formed as pilot berth alcoves off the main room.

Ours is a small one, just 10ft wide and 28ft long.  We bought it because of the unusual layout with a bedroom at each end and the living room / kitchen in the middle.  we would have struggled to get a 12ft wide one to our site.

52 minutes ago, epsilonGreedy said:

Have you sketched an accommodation plan for your temporary accommodation? I ask because a family of 4 will struggle in less than 400 sq ft through a winter, which is large gym in the back garden.

I haven't but I was certainly thinking about over 30m2 which would require BC. At the moment the main question is does it make any sense to build it, I hope I can think of the exact size and layout later. 

10 hours ago, oldkettle said:

I haven't but I was certainly thinking about over 30m2 which would require BC. At the moment the main question is does it make any sense to build it, I hope I can think of the exact size and layout later. 

You can make a "portable building" over 30M² that legally qualifies as a "caravan" so is exempt from building control. It does not even have to be on wheels for that.

35 minutes ago, ProDave said:

You can make a "portable building" over 30M² that legally qualifies as a "caravan" so is exempt from building control. It does not even have to be on wheels for that.

I get it, but does it change anything wrt the accommodation during the build? BC is a different problem, "I will think about it tomorrow" (c) ?