Garden room - make water tight and insulate

[Nettlee]

Hi - we have a decent sized outbuilding which sits in a sturdy base that we plan to convert and make water tight so it can be used as an outside room (workshop or office not decided).
The structure appears sound and it’s been here for 20+ years (neighbors dad used to live in our property and helped out it up).

We plan to run cables for electric etc. but what we are trying to plan at the moment is what we need to do to make the building water tight and insulated.

Understand we would most likely need to insulate the floor, put a new roof on, door and windows in as well as cover / render the outside and insulate / membrane and board the inside up.

Wanted to reach out to see if there were any suggestions on how best to do this. My partner and I have some limited building experience through renovating our own home but wanted to understand if someone has done something similar for a similar structure and what may be the best way to go about it.

My main concern is the floor as there is currently no subfloor and doing so would require us to raise the door threshold, 100% how high threshold would be required or how to go about that exactly.

 

[JohnD]

Is it a sectional concrete building?

 

[Ivor Windybottom]

Honestly, it's not worth keeping. Your plan sounds like making a silk purse out of a sow's ear, or a much cruder phrase involving polishing! Get rid, start again.

It won't fall down, as it's made of concrete - at least not until the bolts rust through anyway. But it won't have a damp proof course and probably doesn't have much in the way of foundations, so if you were to add substantial weight (e.g. a second external wall, insulation), then you may find it all cracks and/or sinks.

Depending how old it is, there's a chance that the roof may contain asbestos. Impssible to tell from the photos, you need some testing. If so then that should make your decision on whether to keep it very simple.

I'd hire a crusher for the day, put the walls and floor slab through it (definitely NOT the roof!) and turn them into hardcore you can use under your new floor.

Sorry that this isn't the reply you were hoping for.

 

[Ivor Windybottom]

You should be able to hire one of these shed improving machines for about £300/day...

https://redrhinocrushers.co.uk/products/rr-4000-series/

Provided that the panels don't contain steel bar or mesh reinforcement - actually they may well do. If so then just smash them with a hammer, or get rid of them.

 

[Ivor Windybottom]

Actually there's a chance that you may be able to make use of the existing floor as-is if you were to build new walls around it and put a higher floating insulated floor over it. If it's definitely solid, reasonably smooth not cracked and is completely level.

 

[Nettlee]

Thank you for the comments. Yes it is a sectional concrete structure.

We had an asbestos check when we moved into the property and there was none in the outbuilding and everything else we have had removed.

Thank you for the input and useful to get the new that if we get rid of it it’s not a loss.

 

[mrrusty]

Start again - it will be almost the same cost. Perhaps a SIPs building? structural, and insulated in one go. Clad it in your choice of materials. https://www.simplysips.co.uk/products/

 

[JohnD]

You can carry on using it as a shed until such time as it is convenient to rebuild.

 

[noseall]

Hi - we have a decent sized outbuilding which sits in a sturdy base that we plan to convert and make water tight so it can be used as an outside room (workshop or office not decided).
The structure appears sound and it’s been here for 20+ years (neighbors dad used to live in our property and helped out it up).

We plan to run cables for electric etc. but what we are trying to plan at the moment is what we need to do to make the building water tight and insulated.

Understand we would most likely need to insulate the floor, put a new roof on, door and windows in as well as cover / render the outside and insulate / membrane and board the inside up.

Wanted to reach out to see if there were any suggestions on how best to do this. My partner and I have some limited building experience through renovating our own home but wanted to understand if someone has done something similar for a similar structure and what may be the best way to go about it.

My main concern is the floor as there is currently no subfloor and doing so would require us to raise the door threshold, 100% how high threshold would be required or how to go about that exactly.

If you are prepared to lose space and headroom, then you could make it more comfortable in there, as long as the doorway height is not compromised too much.
However, as others have said, 'polishing a turd' is not always a good use of your hard earned cash.