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How to renovate and split a garage into two halves?

Paddy1
Just Starting Out

How to renovate and split a garage into two halves?

Hi all


First time posting here but often inspired by other projects and the advice shared by others. I'm certainly no DIY pro and will no doubt get terms wrong so bear with me!

 

I'm planning on renovating my garage and essentially splitting it into two halves - one for typical storage and the other to use as a gym. The garage itself is not in awful condition but it's not great either. It was clearly made a long time ago and looks like it was put together DIY style. The garage is set far back from the front of the house, effectively in the back yard. We don't use it for car storage and all sides are exposed (i.e., the garage is a standalone building - not joined to any part of the house). One of the long sides forms the boundary between me and my neighbour.

 

The main issues for me are

  • The roof is made from metal sheets which means lots of sweating in the winter months. The droplets dry leaving a white residue which is very hard to remove. This means we currently need to cover everything.
  • The two louvered windows are set in rotten wooden frames. The panes don't fit together well, have cracks and there are plenty of gaps in and around the frame / slats. A lot of dust & dirt must travel through.
  • In some parts of the garage, the walls (built with concrete blocks) don't reach all the way to the roof so there's a gap (again, perfect for dust & dirt to come inside).
  • There is a single door (hollow core door) at the back of the garage (with an electric roller door at the front) which is built into a poorly made door way with wooden panels above the door frame rather than bricks.
  • There are other smaller gaps in the brickwork, all at the top of the walls where they should really join the roof without any gaps.
  • There is an inevitable gap above the roller door which I think I'll have to live with.
  • Electrics are dated and built up of daisy chaining extension cords. Needs updated by an electrician.
  • The walls are made of concrete with paint peeling off.

So far, I've decided I want to do the following:

  • Insulate the roof. I've done a little research and am considering sticking this to the roof https://www.bunnings.com.au/moroday-750-x-10mm-x-1-8m-adhesive-foam-roll_p4000005. I wonder if I should go a step further and build a roof cavity (about 200mm), fully insulate and then build a new interior roof? The problems I see are that the garage roof is constructed using steel joists and these metal panels. I can't work out yet how to build a roof frame or attached a new 'false' roof to the existing roof.
  • Insulate and update the walls. These seems quite 'straightforward' in that I feel I need to attach timber frames to the existing walls, insulate the cavity and cover with gyprock. I'd need to plan around the door frame, and existing windows, electrics.
  • While building the frames, I envisage making sure there is a stud that lines up with the half way mark in the garage so that I can use this to attach a partition wall. The floor is concrete and so I'd need to secure the bottom to that. I haven't thought about how to attach it to the roof just yet.
  • The front half of the garage with the roller door entrance (and no windows) will be the storage half. I think once the gaps are filled, and walls complete, this is the easier to paint and prep for use (excluding the roof issue).
  • The back half of the garage (with the single door, and two windows) will be the gym half. This is the tricker half to update. I want to seal up one window which is really not needed. I want to retain the other window but replace the frame and glass. I need to replace the back door (which will be the entrance / exit into the gym half) and reinforce the door frame. I had considered sealing up the doorway and having a door entrance from the storage side (via the new partition wall). I'm still open to this and think this might make practical sense but thought it easier to create two separate rooms, make use of the existing door way and use the full wall on the storage side for storage (otherwise I'd have to leave space for a door way and that doesn't seem efficient).

This is as far as I've got in terms of thoughts / plans and descriptions. At this stage, my main questions are:

  • What's the right order to approach this? I think i need to fix all windows, doors and gaps first. Then sort the roof. Then build out the walls while having planned how the electrics will run). Sound about right?
  • Any reason why I shouldn't just use the existing door way?

And happy to receive any tips or feedback. I've attached some quick photos but can send more once I've decluttered the garage a bit more.

 

Cheers and thanks in advance!20230813_163745.jpg20230813_180547.jpg20230813_163812.jpg20230813_163802.jpg

 

MitchellMc
Bunnings Team Member
Bunnings Team Member

Re: Renovating and splitting a garage into two halves

Welcome to the Bunnings Workshop community @Paddy1. It's wonderful to have you join us, and many thanks for your question about converting a garage into two rooms.

 

There's a fair bit to unpack there, but your approach sounds quite reasonable. Fixing the windows, door and gaps and then moving on to framing makes sense, as then you'll be able to connect the partition wall to the roof frame. In regards to the roof frame, you'll need to run additional timbers across the span. If there is nothing for them to attach to, they'll need to be of a calibre to span the distance unsupported whilst also being able to bear the weight of your plaster sheeting. Your partition wall will be one of their mounting points and will support them midway, so it might be best to construct the wall first.

 

I'd recommend using traditional insulation in the cavity as opposed to Moroday 750 x 10mm x 1.8m Adhesive Foam Roll, as it will have far better insulating properties.
 

Perhaps when you supply more photos, you could sketch out a floor plan to better illustrate the two doors and how they'll function. That way our members will be able to provide their thoughts on access.

 

Here are a few helpful step-by-step guides:

 

 

 

 

You also might like to follow along with @ivanptr's project: How to convert garage into a second living room? 

 

I look forward to following along with your project and please let me know if you have any questions.

 

Mitchell

 

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Re: Renovating and splitting a garage into two halves

Thanks @MitchellMc - great tips for me to start thinking about, and thanks for linking @ivanptr's project too.

 

Only question for now: Is a roof cavity pretty much a must do? I assume I'd fill in as many gaps around the current roof as possible, attach a frame to the current ceiling, fill the cavity with traditional insulation like you've suggested, and then seal with plasterboard (attached to the timber roof frame)? Is it necessary to line the current roof? I assume it would be to try and prevent future sweating being absorbed by the insulation that will be in the roof cavity? 

 

If this is all correct, I've started to think about how to attach the roof frame to the current roof. I noticed there are three small ledges along the long sides of the garage which I could rest the sides of the frame on but am not sure that'll be enough to sustain the weight of the entire frame as there's nothing else to support it across the main section of the roof (2700mm wide). Is it possible to attached the frame to the current roof if I drill into it from above? I think that would work assuming I seal all around the screws from on top of the current roof (outside)?

 

I'm tempted to start in one section of the roof, front or middle as it requires the least effort as a trial.

 

I've attached a diagram of the garage below to help give a better idea of the layout and dimensions. Hope it's not too confusing. A = the back doorway (proposed entry into the gym space), B = window space that will be retained but it really needs better support above the window (at the moment it's a window that goes all the way to the top, C = window space that I propose to fill in and D = the entry to the front of the garage via a roller door that goes across the entire width and height of the garage. The three pillars you see on each side are the 100mm x 300mm pillars on the inside of the garage to give structural support for each of the three steel beams that run across the width of the garage but they don't go all the way to the top of the garage as the beams rest on them. You can see these in the images in the last post.

 

Final question - what's the suggested depth of roof cavity? Would 200-300mm suffice?

 

Thanks again

plan2.png

 

MitchellMc
Bunnings Team Member
Bunnings Team Member

Re: Renovating and splitting a garage into two halves

The roof cavity is not a must-do @Paddy1, but if you want a roof lining sheet for aesthetical reasons, then you'll need some framework to attach it to. Sarking is typically used to line a roof to ensure any water ingress gets taken out of the roof, not really for sweating as such.

 

Best to use a calibre of timber that can span the gap than try to attach it to the roof. Sheeted roofs are not weight-bearing structures, and the fewer holes you put in them, the better.

 

The roof cavity could be as thin as 90mm, depending on the calibre of timber needed for the span.

 

Mitchell

 

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