Garden room project

[Humf]

I'm gradually finding my feet with SketchUp. Very early days so far and I'm sure there's things I'm not doing as quickly and accurately as possible e.g. the 'snap' function when joining timbers doesn't seem as intuitive as I'd like.

Just done the base so far, converting the hand drawn sketch above onto the app. Foundations next.

 

[Humf]

your issue for planning doesn’t need an architect - they will be happy with a pencil sketch and location plan downloaded off one of the OS map providers. Your issue is size and you are in building regs territory over 30sqm so I would seriously consider reducing the size / length slightly which will mean you don’t need approvals on structure / insulation / etc.

You could retain the total length as designed but add an open / covered area to one end so you would have an 8.4m internal space with a 1.2m open end - this wouldn’t need BRegs approval but would be just as useful.

Also consider your roof design - a standard 22.5° apex roof will need around 8m of timber per truss profile, a 5° mono pitch will use half that. The apex roof will also require around 8-10% more covering, double the length of guttering and so on.

If you want to get a lot of light into the shop but retain some security and wall space then also using a celestory or high level window would also benefit - using your panel design to create a rectangular box, you can then add on the top lights all along one edge which will increase light into the build but also mean you maximise wall space internally.

I'm running with this idea and trying the building slightly shorter, at 8.4m x 3.6m. This leaves 1.2m of covered decking. I'm also planning to run the raised decking around the front too but not including this on the plans yet.

Since the 1.2m will be covered by the roof, I'm including this within the base design, as the roof above will need proper support. The original layout of the concrete blocks was an even spacing but I've added an extra column of blocks sitting underneath the new corner at 1.2m.

I'm not sure of the best layout tbh... (for info - I'm also going to develop this design with a pent roof)

 

[PDW125]

For the sake of a few blocks, I think spanning 2.4m between piers is going to be pushing it especially with equipment etc loadings on the floor. I would go with 1.2m spans assuming these are single block on flat piers.

 

[Humf]

The blocks I have planned are the large high density hollow blocks. I have quite a few remaining from a professionally built retaining wall. They measure approx 440 x 220 x 220. My plan is to place two, side by side, and fill with rebar & concrete, driving the rebar down into the rocky ground below. I’d estimate I could achieve between 0.5/1m of depth for the rebar.

The blocks will sit on a 880 x 880 size sub base of either type 1 or concrete, to a depth of approx 300mm. Not sure what’s best, compacted type 1 or concrete.

I’m reluctant to go as substantial for any intermediate blocks. Feels overkill. How about some standard 7.3N ones belly down, for the 1.2m supports in between my main piers? Is there any risk when mixing different size piers?

 

[Humf]

If I’ve got my calcs right, then the spans between piers are currently:

2400 - 220 - 220 = 1960

Which I think is ok for 6x2 at 600mm centres. But I take your point…

 

[PDW125]

I’d just use them as they stand individually - won’t go anywhere if they are sat on a concrete pad and the rebar is probably only going to stop them moving sideways so 500mm tops will work.

 

[Jameshow]

I think you'll be perfectly fine.

I cannot see it going anywhere.....

 

[Humf]

Thanks both. Currently working on a version that sticks with the main piers as shown (440 x 440) every 2.4m but adds single blocks (220 x 440) at the 1.2m points. Bit of a hybrid but I’ve got married to the idea of the main piers being 2 blocks!

 

[morqthana]

Some random points.

I've not used the latest version of Sketchup, so I can't be sure, but my prejudice says that an online tool accessed via a web browser (?) is going to be clunkier than a local app. There are sites which have archived old versions of free software - see if you can track down Sketchup Make 2017?

Remember that Building Regs threshold is internal floor area, not external building footprint. That said, obviously you want to avoid paying the oh-so-reasonable fees, but actually complying with the regs oughtn't to be a problem, unless you're building a ramshackle fally-down deathtrap of a shack. Which you're not.

Part P applies whatever though, but the electrician for the main work will be able to take care of that. Do you know what size the existing cable is? Better to be too big at first than too small in a few years time if your use changes and you need to trench a bigger one in.

Ditto other services, if they won't give planning a hissy fit (hint - don't tell them about water and drainage if you aren't proposing to use/connect them in this shed)

I don't know if Article 2(3) makes a difference, but if you build it so that it is capable of being moved as a complete structure (even if access realities mean you'd need a Sikorsky to do it) you may be able to avoid PP as it will count as a caravan.

And as for access - you can get micro diggers which are only 69cm wide.

Consider an ASHP for heating. (And cooling )

 

[MikeJhn]

Instead of blocks what I have used in the past is concrete fence posts, my office shed has been there for about twenty five years without moving and its on a slope.

 

[Humf]

Anyone seen these insulated panels before? I’m not really interested for the main structure but they sell them as roof panels only to be fixed onto timber frame buildings. Looks neat.

 

[Humf]

Thanks for your input Morq and Mike. Will reply properly when I’ve had chance to consider.

 

[Mdhazell]

Anyone seen these insulated panels before? I’m not really interested for the main structure but they sell them as roof panels only to be fixed onto timber frame buildings. Looks neat.

Anyone seen these insulated panels before? I’m not really interested for the main structure but they sell them as roof panels only to be fixed onto timber frame buildings. Looks neat.

They are an off shoot from Kingspan from what I can see. I've been looking at one of the buildings for my homebrew setup. Basically, it is Kingspan insulation sandwiched between 2 x 0.5mm sheets of treated steel. They reckon it is impossible for the steel to rust due to the process it goes through.
Hope this helps.
Mark

 

[morqthana]

I assume that counts as substantially non-combustible, given how close it is to the boundary. Talking of which, I don't know whose fence that is, but if it's his he'll regret not replacing it while he could still get at it.

As for speed - I recently had a 3m x 11m log cabin built in about 1½ days.