# Garden Office build



## LarryS. (9 May 2020)

Hi all, 

A couple of months ago I was on here asking about converting our summer house to a garden office.

Since then things have changed in terms of my job looking like the home based status will continue long after coronavirus, and we should have some money left after some landscaping / possible extension we are having done, which we’ve reduced the scope of (so I’ve got more money to spend)

So

The thinking now is to take out our relatively new shed, and put its contents into 2 smaller sheds elsewhere in the garden, and use its prime spot and base for a purpose built office (8ft x 10ft).

So my plan is to build it as close as I can to “mikes way”, accounting for the base already being there without a DPM under it.

It’ll be a pent shape to keep height low for the neighbours. So next step will be a sketch up drawing for me to get my head around the concept, and I’ll be sharing photos / thoughts here for any input I can get.
The design will be along these lines
https://dunsterhouse.co.uk/titania-garden-office-w3-3m-x-d2-7m

Timeline, I’m guessing 2 or 3 months to get started , so I’ll be hoping to finish it relatively quickly before winter sets in. Being only 8 x 10 hopefully I can do most of the framework in my garage workshop and keep the outside work to a minimum

Some photos attached to show you the general position, and yes it’s within 1m of next door (about 80cms) but as it’s an office I’m going to try and ignore that (it’s got less to worry about in it than the shed has!)

















Sent from my iPhone using Tapatalk Pro


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## LarryS. (10 May 2020)

So here is my start of a sketchup plan, any / all feedback welcome if i'm on the right track. I get the feeling i'm over-engineering this - but that's my usual default


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## LarryS. (11 May 2020)

couple of questions I'm hoping someone can elp with

1. do i bring the shiplap down to ground level (if i don't do the brick layers at the bottom of the frame, i'm considering skiping them as the concrete base is mostly 4 inches above ground)

2. under the door i'm presuming i can put in a couple of steps (to save the shiplap going across underneath the door, which would look odd ?

any help appreciated, thanks

Paul


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## MikeG. (11 May 2020)

Don't skip the brick plinth. It is THE critical factor in the longevity of your building.


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## DBT85 (11 May 2020)

I'm not sure how readily you can just ignore its distance to the boundary?


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## MikeG. (11 May 2020)

DBT85":2d2zjk9e said:


> I'm not sure how readily you can just ignore its distance to the boundary?



It's under 15 sq m so the BR thing doesn't apply. Height is the only issue.


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## LarryS. (12 May 2020)

so the brick plinth is back in  and now starting to get down to some real detail on the drawing, including batton layout. I always struggle to visualise something in 3d so i'm planning to put this drawing in some real detail so i know exactly what i'm doing, and can work up a plan and order the materials hopefully in the right order.

Can anyone sense check my batton placements and see if they lok sensible (particularly the corners) ?

Also as I don't have a DPM could I lay one on top of the slab, and loop it up over the 2nd brick ? And then lay the 50mm insulation and chipboard flooring onto that ?

thanks again

Paul


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## DBT85 (12 May 2020)

Only thing from me is have you considered 610/600 spacing on your studs (depending on the width of your sheet goods) and don't forget your noggins.


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## MikeG. (12 May 2020)

LarryS":og0mz1mn said:


> ........Can anyone sense check my batton placements and see if they lok sensible (particularly the corners) ?.......



sp: Battens. 

Here is my corner detail. It involves replacing one of the corner counterbattens with a 4x1 (3x1 at a pinch), which has a ripped 3x1 screwed to it at right angles:






If you work your way through myworkshop build thread at WH2 you'll see the corner detail in photos. It may be a useful read for you anyway, and isn't terribly long.


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## MikeG. (12 May 2020)

Back to your model.......

If your roof is oriented in the way you indicate in your opening posts, then you'll need a proper lintel across your big window and door openings, instead of a doubled-up plate as you've shown. I'd say instinctively that a pair of 145x45s pinned together will be fine.


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## RobinBHM (12 May 2020)

And dont forget the insect mesh to close off the 25mm cavity!

I think the advise is to have the cavity open at top and bottom -I dont if Mike agrees?


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## MikeG. (12 May 2020)

Mesh at the bottom, certainly. If it was an impervious covering, such as render, then I'd specify mesh at the top too, but there is enough air leakage through feather edge boards that I'm quite happy to close the top off with a piece of wood.


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## LarryS. (18 May 2020)

Hi Mike,

Just read through your build and it reminded me about your 50mm block inner wall, i'd missed that detail off so will add it back in (i'm presuming it's the only way to avoid the overhang)?

I've added your corner detail so thanks for that, and the 6x2 joists across the front to support the roof.

Reading another garden office thread you've replied to it looks like you'd suggest a 25mm layer of insulation on the inside of the framework to cover the bricks cold bridge, is that the most straightforward solution? I think it will be relatively straightforward to change to 75mm between the framework uprights, could that mean I can forgo the battens and use the outside 25mm as the air gap? I'm gerssing not as there is no airflow at the top and bottom?

thanks

Paul


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## RobinBHM (19 May 2020)

MikeG.":21m2zckc said:


> Mesh at the bottom, certainly. If it was an impervious covering, such as render, then I'd specify mesh at the top too, but there is enough air leakage through feather edge boards that I'm quite happy to close the top off with a piece of wood.



Many thanks

Yes I couldnt decide, an architect I know insisted it was necessary, so I ended up going down that route -which is a bit of a pain as it means the I need some extra timber to dress down over. 

Your argument that there is sufficient air leakage through the featherdge makes perfect sense -mine is Siberian larch which is pretty tight fitting, compared to say green oak, but all the same it must have air leakage to allow air flow.


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## MikeG. (20 May 2020)

LarryS":102n7nth said:


> ....... your 50mm block inner wall, i'd missed that detail off so will add it back in (i'm presuming it's the only way to avoid the overhang)?



It's just about the only way if using 95mm framing. I am shortly going to be building a bike shed and will probably use 70x45s for the frame, as it is a relatively small building (3.1m x 3.9m). It's a bit bouncier when nailing on the FE board, but that's OK. I previously did a 2.4 x 2.4 shed in 45x45 framing, and that worked out really well. It puts the outside of the frame at about the same relationship to the outside of the brickwork as with a 95x45 frame on a 160mm thick plinth. 



> Reading another garden office thread you've replied to it looks like you'd suggest a 25mm layer of insulation on the inside of the framework to cover the bricks cold bridge, is that the most straightforward solution? I think it will be relatively straightforward to change to 75mm between the framework uprights, could that mean I can forgo the battens and use the outside 25mm as the air gap? I'm gerssing not as there is no airflow at the top and bottom?......



I'm not following this very well Paul. My suggestion was for an extra 25mm of insulation over the inside face of the studs. Nothing else changes. There MUST be a 25mm clear gap behind the cladding, outside the frame, and I've never proposed filling that. The only way to achieve that is by vertical battens at each stud location. I'f I've not understood what you are proposing, let me know.


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## LarryS. (20 May 2020)

thanks Mike, I'll look at the smaller framing as an option to possibly simplify the build, the building is 3.6m x 2.4m so relatively small

On the other idea, i was originally planning 100mm within the frame, and then 25mm battens outside and then the cladding on top. What i was thinking was if I was going to add 25mm instulation on the inside of the frame (to cover the brick cold bridge) then i could reduce the frame insulation to 75mm and achieve the same insulation level. 
And then within the frame the 75mm insulation would leave a 25mm air gap on the outside. 

I guess the idea is probably mute now anyway if i go for 75mm framing 

thanks for the help

Paul


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