3. Design your garden room
Brilliant, now you’ve got a good idea of what you’ll be using your garden room for, the size you want it to be and the regulations you need to stay within if you want to avoid planning permission and building regs!
Now is the time to get all that down on paper – or better yet, SketchUp!
Have a watch of the video and as usual we’ll discuss below.
SketchUp
As you can see, my SketchUp drawing isn’t perfect and it really doesn’t need to be. Whether you need to have a millimetre-perfect drawing or not will depend on your ability to hold a design in your head and understand how everything interconnects – and everyone’s different.
However, I’d highly recommend getting at least a rough design done on the program to better visualise your garden room, calculate quantities of building materials and give you a firmer understanding of wall-framing (all of which will help convince the other half too!).
You can download SketchUp here. Once you’ve got the hang of it, it’s an easy program to use and there are plenty of educational YouTube videos out there. You can also get my own rough SketchUp design for free here and can tinker with it to your heart’s content!
Planning on paper is a good alternative and how I worked out material quantities for each stage.
Why timber-frame?
Okay, I’m biased because I love working with wood. We’re less familiar with timber-framing in the UK but it’s the most common form of house building in the US and elsewhere. It’s also become popular for new-builds in Scotland which shows it holds up well against the elements. There are other advantages too:
- Lighter – That means your foundations don’t need to be a metre deep as you see on many house extensions.
- DIY friendly – It’s easily cut even with a handsaw and as a material is more malleable than it first appears and with a few screws can be held in place.
- Thermal efficiency – Sure, if you don’t insulate over it (internal or externally), it creates a thermal bridge whereby heat is lost faster through it than the insulation, but it’s a lot better than brick or blocks. Imagine touching a tree trunk on a hot sunny day or in the depths of winter – doesn’t feel too hot or cold does it? Now do the same with bare feet on a paving slab! The principle is the same.
- Wall width – Because of the above point, block and/or brick requires two walls with a cavity in between and that means a very wide wall which may well eat into your garden room’s floor space. My timber walls are no more than 15cm thick and that includes plasterboard and cladding.
- Eco-friendly – The carbon the timber contains is locked up in your garden room and as long as the trees are replanted, it’s a renewable resource. Timber, when kept dry can last indefinitely but at the end of its life it can be burnt or composted, not dumped in landfill.
- Easy electrics and plumbing – No chasing out block walls or trying to get cables in SIPS etc.
What other options are there?
- SIPS – Insulation sandwiched between sheets of OSB and fast method of building. These can be used for floor and ceiling too if the span isn’t too wide. This is the second most common method for garden rooms.
- Brick or block – If you want to minimise wall width you can do a ‘single skin’ block wall (i.e. no cavity) and insulate internally or externally. Cement mixer required though.
- Steel frame construction – There are companies that provide the metalwork pre-cut. It will conduct heat quickly though so I’d advise pairing it with internal or external insulation rather than relying on only insulation between studs.
- There are plenty of other niche building methods: cordwood construction, insulated concrete formwork etc. Until they become more mainstream, they’re best left to the more intrepid builders.
Size and shape
I knew I wanted to build to the maximum size without requiring building regs. Because of the shape of my garden my design was quite square: 6.5m x 5m. This is a very large space so if you have less room a smaller size will still be adequate for what you want from it. Dimensions of 4 x 3 or 5 x 4 metres are pretty common.
Many garden room designs incorporate a separate space for garden tools or a small workshop while keeping the other side available for leisure.
Because of the width of mine (5 metres), it’s harder to partition – so longer and thinner is better for this. I think my ultimate garden room would be 8m x 4m! A thinner garden room also has the advantage of reducing the span of your roof joists which = thinner and cheaper joists.
Just remember, the larger it is, the greater the cost and time to build it.
Graeme Staddon’s 8m x 2.8m partitioned garden room
Use
As you heard in the video I want my garden room to be all things: a wood workshop, an office, a games room and even the potential to be turned into an annexe (that would need building regs approval and planning permission change of use). I even want it to be a gym and lads hangout if I could. Greedy? Perhaps, but I think versatility is important and certainly achievable.
A garden room, once built, can be used for most things but here are some considerations depending on what you want it for:
- Games room – enough room to swing a cue!
- Art studio – big windows to let that morning light inspire you.
- Gym – enough ceiling height to lift weights above your head.
If you’re building a guest house or annexe, you can use SketchUp to add a bed, table and kitchen but even easier is Opun Planner or Room Styler (recommended by viewer Jon Macrae)
Don't make the biggest mistake
There are too many options and variations in styles, materials, building methods to discuss here. Have a look at the ‘Your Builds’ section of the website to get inspiration from others and come up with what works for you and let’s focus on the key issue: Ceiling Height!
However you design your garden room, ensure that you have at least 2.1m head height once you’ve accounted for: foundations, floor joists, ply, flooring, ceiling plasterboard, ceiling joists, insulation etc. If you are building under 2.5m you’ll soon see that 40cm gets eaten up quickly, so get the design correct now.
Planning permission
If your design just doesn’t suit permitted development then now is the time to get planning permission in.
You don’t need an architect or a special CAD program, the purpose of planning is simply to give the planners an understanding of what the garden room will look like and whether it’s in keeping with the surrounding area, especially if it can be seen from the road. Simple hand-drawn sketches will suffice.
I recommend meeting with a planning officer first – it’s free and will give you the chance to find out anything they don’t look kindly on (in my area ‘beds in sheds’ are a concern). Having met a planning officer prior to applying will often mean the project will be looked on more favourably. Sometimes it’s worth pointing out with a covering letter how you’ll be deviating from permitted development. For me the only difference was to increase the height by 0.5m.
What does the application entail?
Your best bet is to look at other applications for extensions etc and you’ll see they include:
- a plan-view of the floor-plan, the location in your garden, compass and scale
- the four elevations (sides) with scale
- a block and site plan which can be bought online for your house
In reality these first 3 videos aren’t really in any particular order. Once you get designing you’ll find yourself going back and looking at the site and checking the permitted development rules so sometimes it feels like 2 steps forward, one step back.
Task: Bring the intended use, your site restrictions and knowledge of permitted development into a great design. It’s okay if it’s not down to the last nail, you’re probably ready to get stuck in now so let’s get in the garden…