Please Guide my Build!

[hmpmarketing]

If this post is in the wrong forum, feel free to move it! 

 

I am completely stuck on what way I should go with my “garden office” build. Maybe on my previous posts asking for help I wasn’t clear enough on my objective so I decided to write this post in detail and looking for the forum members help to guide this on the right direction.

 

First of all, below is a site plan of my plot to have an idea of the layout. The plot is 40m x 20m, the new builds are parallel to each other, and the “garden office” will sit at the front of property B. I call the project “garden office” simply because thats what the current use the building will be: My work-from-home office (away from my 2 little ones yelling constantly inside the house while I work! ?) and a place for my preferred hobby: Play my keyboard and bass ???

 

 

Due to the size of the plot, the plan for the distant future is to convert this into a 1-bed / granny annex. This will of course be up to planning to decide, but hey, Im getting old and I need to think for the future, maybe this is where I will live when the kids are bigger and want to keep daddy or mummy near them.

 

Currently (and members that have replied to my previous posts here and on e-build may be familiar) I went for approval for a 8m x 6m garage, originally I had a 6m x 4m and managed to get the increased m2 and height. But to be honest, the garage idea was a mistake, I wouldn't be parking cars in there anyways.I have got plenty of space to satisfy the LA requirement for parking spaces. So I went for a variation of a condition (cheaper) to get the new plan approved, below is the proposed new layout and elevation plans:

 

 

 

 

My case officer has been very nice and helpful about it all, since the day we applied for the new builds, and he suggested the site layout above, the current application is on going and I have no concerns of if not being approved. 

 

Unlike my house build which was a turnkey solution (however all external work so far had my hands in it ?️) I want to make this a complete DIY project, however my limited skill-set is what is keeping me from deciding the best route for this as I am willing to do the majority of the work (along with my brother in law). A bricky friend has also made himself available. Apart from stuff like electrics, which I will have to get a specialist to do. Currently I have no plans to install any drainage or gas, only electrics. So everything else, plastering, external rendering, painting, roof we are up for the challenge.

 

Foundations

 

No clue yet! This will be dependant on the shell!

 

Roof

 

One thing right now is certain, a warm flat roof very similar to the one below is what I want to go for:

 

https://www.youtube.com/watch?v=X2oHYzh5PaE&t=20s

 

I-joists to the rescue with that 6m span ?

 

Outer Shell

 

One of my main concerns is keeping it nice and warm during the winter (and future), and this is what is really keeping me stuck: to decide which method to go with the outer shell taking into consideration current building regs and the future.

 

I have spent countless hours reading about concrete blockwork, clay blocks, ICF, timber, SIPs, and tried my best to work out the costs involved when choosing any of them. Budget is also a key point: I don’t plan on spending more than £15k on the project. I did budget for £20k but going DIY should hopefully make the 15k figure more or less what I want to spend!

 

So, I am really looking for guidance here on this, Im humble enough to accept the forums input, and want to make this nearly 100% DIY, so can you all help me out?

[PeterW]

Go and find a local new build housing estate and look at the sales office... usually it’s a converted double garage that they then convert back to a garage by way of two doors at the end. 

 

I would suggest follow this route maybe worthwhile - replace the doors with a pair of French doors and you get light and the ability to “convert” when the time comes to sell etc. 

 

£15k needs to include what ..?? Does it have to be brick or is another wall finish specified on the planning permission ..??

[Mr Punter]

Although you say otherwise, I think you should include provision for electrics, water and drainage, so you can have a WC.  Quite annoying if you have to traipse over to the house and back when it is raining.  A floor plan may be useful.  Maybe don't go for the windows to the floor as they may restrict future kitchenette placement.  Rendered block may be cheapest.

[PeterW]

I’m with @Mr Punter on this - stick a drain connection in and then you can have sink, WC etc. 

[hmpmarketing]

1 minute ago, PeterW said:

Go and find a local new build housing estate and look at the sales office... usually it’s a converted double garage that they then convert back to a garage by way of two doors at the end. 

 

I would suggest follow this route maybe worthwhile - replace the doors with a pair of French doors and you get light and the ability to “convert” when the time comes to sell etc. 

 

£15k needs to include what ..?? Does it have to be brick or is another wall finish specified on the planning permission ..??

 

Hi @PeterW thanks for your reply once again !

 

There is no finish specified, the initially proposed garage also had no finishing materials specified. But it would be white render to match the builds. £15K needs to include all ? ☺️

Just so everyone knows, there is no building where the proposed plan will go

 

[hmpmarketing]

6 minutes ago, Mr Punter said:

Although you say otherwise, I think you should include provision for electrics, water and drainage, so you can have a WC.  Quite annoying if you have to traipse over to the house and back when it is raining.  A floor plan may be useful.  Maybe don't go for the windows to the floor as they may restrict future kitchenette placement.  Rendered block may be cheapest.

 

Thanks for the suggestions. I have taken the provision for drainage into consideration, this will be on my list for sure

 

Currently this is the floor plan:

 

[PeterW]

You have a window pointing straight onto a street and a desk in front of it ....... that’s a licence to have someone break in as the property can be clearly seen...

[hmpmarketing]

Just now, PeterW said:

You have a window pointing straight onto a street and a desk in front of it ....... that’s a licence to have someone break in as the property can be clearly seen...

 

There is a high closed panel gate in the entrance

 

14 minutes ago, Mr Punter said:

Rendered block may be cheapest

 

Rendered block was up on my list, but single skin would require some good 100mm insulation?

[Mr Punter]

If your plan is to perhaps have this as a future habitable annex, place the entrance and windows so it suits the future requirement as well as current.  I can't see how a 100mm block wall is going to be "nice and warm".  You may do better having timber framed walls but you will need non combustible cladding as you are near the boundary.  You may get a small timber frame company to fabricate and deliver the walls and soleplates and supply the roof materials.  They will often get better terms than you will get from a builders merchant.

[Declan52]

I would put the foundations in to suit a 2 storey build. It wouldn't take much to lift the roof of and build up if the need arises  later on. Who knows what you/your kids will need/want in 25 years time. It won't be that much extra concrete but will cover you for any future change.

The cheapest build will be block with a sand cement render painted white. Insulated plasterboard on the inside with the walls parge coated before it goes on. Not sure a single block will be strong enough  how about a 150mm wide wall.

How flexible are you with regards the windows and doors. Do they have to match the house or can you search gumtree/reclamation yards for bargains.

 

Edited August 14, 2018 by Declan52

[PeterW]

You should be able to put blocks up for £30/sqm laid if you’ve got a mate who’s a brickie. There is about 70sqm measured through so that’s £2100 per skin. Insulation should be around £400, leaves you £10k for roof, founds and fit out. 

 

Raft would be quickest and simple - 9 cube would give you 150mm slab across the lot with the edge thickened to 300mm. Lay 150mm EPS under the centre section to create the hump and happy days ... 

 

Use off the shelf JJi for the roof, OSB then GRP and insulate the inside, VCL and board. 

 

If  you use paint grade blocks internally then you won’t need to plaster either. 

 

Should be easily do-able for £15k..

[hmpmarketing]

4 minutes ago, Mr Punter said:

You may do better having timber framed walls but you will need non combustible cladding as you are near the boundary

This was one of my concerns in terms of cost, as at least 2 walls would have to be clad fire resistant

[hmpmarketing]

12 minutes ago, Declan52 said:

I would put the foundations in to suit a 2 storey build.

Good thoughts on this, not sure a 2 storey would go well with the planners, but thats for the future I guess

 

9 minutes ago, PeterW said:

You should be able to put blocks up for £30/sqm laid if you’ve got a mate who’s a brickie. There is about 70sqm measured through so that’s £2100 per skin. Insulation should be around £400, leaves you £10k for roof, founds and fit out. 

@PeterW, you mean double skin 100mm blocks with cavity insulation?

Edited August 14, 2018 by hmpmarketing

[hmpmarketing]

12 minutes ago, Declan52 said:

How flexible are you with regards the windows and doors

Neighbour works for a window company, can get really good prices 

[Mr Punter]

14 minutes ago, hmpmarketing said:

This was one of my concerns in terms of cost, as at least 2 walls would have to be clad fire resistant

 

The Hardie Plank / Marley / Cembrit type boards are fire resistant and easy to DIY.  About £25 per sqm.

[PeterW]

23 minutes ago, hmpmarketing said:

Good thoughts on this, not sure a 2 storey would go well with the planners, but thats for the future I guess

 

@PeterW, you mean double skin 100mm blocks with cavity insulation?

 

Yes

[hmpmarketing]

14 minutes ago, Mr Punter said:

 

The Hardie Plank / Marley / Cembrit type boards are fire resistant and easy to DIY.  About £25 per sqm.

 

Assuming 2 walls @ 42sqm that would be £1k for boards, havent done the figures for all 4 timber walls + insulation yet

[hmpmarketing]

12 minutes ago, PeterW said:

 

Yes

50mm?

[Declan52]

You will need more insulation than 50mm if you want if nice and warm. 150mm is what you should be looking at.

[hmpmarketing]

8 minutes ago, Declan52 said:

You will need more insulation than 50mm if you want if nice and warm. 150mm is what you should be looking at.

 

That will be a thick *ss wall

 

If I remove the need for plaster and use paint grade blocks as @PeterW suggested this would save some internal space 

Edited August 14, 2018 by hmpmarketing

[PeterW]

Either 100mm fibre or 75mm PIR but 50mm will do nothing 

 

other option is single skin with piers and internally clad with 50mm celotex then 37.5mm insulated plasterboard but that will be more expensive. 

[PeterW]

You can’t have all three of warm thin and cheap - pick which 2 you want. 

[hmpmarketing]

Just now, PeterW said:

Either 100mm fibre or 75mm PIR but 50mm will do nothing 

 

other option is single skin with piers and internally clad with 50mm celotex then 37.5mm insulated plasterboard but that will be more expensive. 

Ignore by "newbieness" but what if laying the blocks the other way (so thickness is 225mm) with thicker insulation inside only? I guess this would bring dampness issues?

[Nickfromwales]

1 hour ago, hmpmarketing said:

Neighbour works for a window company, can get really good prices 

Go to a local uPVC manufacturer / supplier and make the openings to suit whatever 'mis-measures' they have for sale. Means buying the windows and doors up front but could be less than half price.

Cant you squeeze it over a 1000mm away from the boundary and then avoid complex 'fire proof' finishes ?

 

Do you think you'd get pp for room in roof over a conventional garage? Or too much ? ?

[hmpmarketing]

1 minute ago, Nickfromwales said:

Go to a local uPVC manufacturer / supplier and make the openings to suit whatever 'mis-measures' they have for sale. Means buying the windows and doors up front but could be less than half price.

Cant you squeeze it over a 1000mm away from the boundary and then avoid complex 'fire proof' finishes ?

 

Do you think you'd get pp for room in roof over a conventional garage? Or too much ? ?

 

HI @Nickfromwales thanks so much for your reply.

 

just for quotation purposes, I have quoted upvc windows, they would come up at around £190 each supply only, external anthracite color and white internally, is that a good price new? 

Regarding the door, on my build they stained one of the doors and I had it replaced for free a couple of weeks ago, I now have this beautiful aluminuml door sitting inside a OSB box that I will re-use for this build. Only thing is, the frame (SCHÜCO) is 450EUR!

 

 

I could move slightly from boundary,  I think 1.20m would avoid fireproofing? This would only be if I choose timber frame instead and finding it difficult to do with my skill set!

 

The actual approved garage plan was to have a room in the roof, but I think it would be costly as I would have to add stairs, etc, and this would be over my budget surely!