Garden room renovation - Details

[OSA]

Hello everyone, we have a garden room which we would like to renovate. We have some builders lined up who have done work for us before, I just want to get clued up on our options and decide the best course of action. 

 

The room:

* 5m x 7m rectangular shape

* Built from breeze blocks and bricks

* Concrete floor

* Apex roof, tiled like a house, flat plasterboard inside 

* Render on the front, painted inside

* Dedicated power on a separate box under the stairs etc. 

 

What we intend to do:

* Tile the floor with 20mm porcelain tiles we already have, from a different project. 

* Replace the horrible sagging plasterboard ceiling - ideally following the roof shape to increase head height

* Increase the opening from one door wide to probably 2 doors and get sliding doors.

* Line the walls, probably eith plasterboard 

* Other bits and bobs like new lights, etc

 

Basically make it a decent blank canvas. 

 

My main questions are around insulating it and wall materials. 

 

Floor:

Solid concrete, having 20mm porcelain tiles - is it worth insulating it, if so, how? 

 

Walls:

If using plasterboard, can we just use the stuff with insulation attached? - do we need anything else? 

 

Would ply be a good alternative to plasterboard, as in my view it's much better for hanging stuff off. (One part of this room will remain a shed). 

 

Roof

We don't know fully what were dealing with here until its opened up, but I assume just insulated plasterboard again? 

 

I read somewhere else sbout breathable membranes, but I'm not sure how that would fit into the equation here, if at all. 

 

Any hell much appreciated, I've done some reading over the last few days and I'm going round in circles! 

 

[Redbeard]

Hi and welcome.

 

You wrote: "Any hell much appreciated"

 

We promise not to give you any!!

 

And now seriously...

 

Generally: Please Please Please Please Please Please insulate, as much as you can, now. You will have loads and loads of time to regret not doing so, or doing it insufficiently, later.

 

Having said that...

 

Floor. Yes: Insulate. Any is better than nothing at all. At risk of having to do a bit of door-chopping (can we have pics, as I might not be so blithe on that if it's a uPVC door) how about 25 or 50mm PIR (Kingspan/Celotex-type), damp-proof membrane as vapour control layer, taped at all joints and perimeters, T&G OSB18mm with glued T&G, then your tiles.

 

Walls: Gov't best practice guidance (search BEIS, best practice, solid wall retrofit) suggests that if you are using anything that is not 'vapour-open' ('breathable') you should have a *ventilated* cavity behind the insulation. Some have been doing it otherwise for many years without issues but I understand they (the gov't) have v knowledgeable advisors and good reasons (interstitial condensation risk) for their suggestion.

 

Anyway, more from me or others later. Got an extension to finish!

[OSA]

Thank you for your reply, much appreciated. Attached is a picture of the floor and the door. We do intend to get new doors.

 

I think critically it will depend how much we can open up the roof area, as at the moment wanting to drop an inch or two even off this height wouldn't be desirable. 

 

Also attached is a picture of the inside, please excuse the mess - this is the result of putting all the garden toot into the shed to allow someone to tile the patio, leftover tiles from two bathrooms (to be used later!) and lots of decorating equipment, as thats another project in the house! 

 

This gives you an idea of the height, incidentally, those bits that jut out, are they called piers? 

 

Thanks. 

 

 

Edited March 25, 2023 by OSA
Typo

[OSA]

Thinking more about the height of the floor, I think it may be good to match inside and outside heights, as many do between kitchen and garden. A step up into the garden room probably isn't ideal. 

 

How can I find the information on the difference insulation makes in its different forms. One end of the scale is basically none, laying straight onto the concrete slab with tile adhesive, done. The other is as you have kindly outlined above. It sounds lame but is it basically 'it reduces cold and damp in the room'.. 

[Radian]

Architecturally speaking, the UK national standard sets a minimum floor to ceiling height of 2.3m for at least 75% of the floor area. This rises to 2.5m for London because they're posh. Your floor to ceiling height looks to be more like 2m?

You're talking about raising the ceiling but there's a good chance the roof is constructed from triangular trusses spanning between walls and the only way to raise ceiling height is with raised tie trusses which would mean replacing the whole roof.

Or have you discovered something else about the roof construction?

[OSA]

Interesting, thank you. I would have to measure it, however, I'm 5' 9 and I can touch it, indoors where were. 2.45-2.4 or so meters I cannot. 

 

So essentially you're saying there is probably a triangle of timber like you would see in a loft which is above this manky plasterboard. That makes sense - there must be something for the (too short!) nails to attach (poorly!) to. 

 

I wonder of those timbers could be replaced with bigger nicer onesthwt could be a feature, and we could still plasterboard the roof following the profile of the tiles. 

 

Replacing the roof isn't really someone would want to do right now. I guess I'll know more if we took a strategic plasterboard down and had a look. 

 

Whilst it will make the height lower if we insulate I guess if its skimmed and painted white it may give the illusion of feing bigger than now! 

[OSA]

Here's a, side view. 

[OSA]

And here is a shoddy picture showing the roof a bit better