Help completing a Garden Room

[efunc]

No, I'm not suggesting that you raise the height. Merely that you support it one side at a time, and shave around a foot off the bottom. A new sole plate (horizontal bottom timber) would need to be fixed to the bottom of the shortened studs.

Three courses of brick, maybe.

ok, thanks for clarification. It sounds a bit of a challenge so my main task will be finding someone competent enough to do what you suggest. I like the idea though if someone's able to do it. I would be happy to reduce the door heights from 210cm to about 200cm too, but does that mean the new sole plate would be terminated at the doors/windows and that these would be sitting on the brick plinth instead? Otherwise they would be about 30cm shorter. Also, where should the acrows be positioned, because the frame is no longer exposed anywhere.

If anyone can recommend a builder for this in NW London I would be very interested.

 

[securespark]

Regarding the wiring, depending on the load, you may not need a consumer unit.

Is the outbuilding going to be a place of relaxation? You may not need a dimmer.

But as for that rat's nest in the ceiling, I'm not sure why they did it that way.

Essentially, all you need is a feed to the switches from the supply (be that via a CU or a 3/ 5A FCU), a single cable out to the inside lights and another to the outside lights, from which you feed the others and SWA connected to the outside switch, the house end of which is also connected to a switch. Then you need a feed out from the supply (either the CU or the supply side of the FCU feeding the lighting) to pick up the sockets.

And you need RCD protection.

I assume there is no water in this outbuilding?

 

[efunc]

Regarding the wiring, depending on the load, you may not need a consumer unit.

Is the outbuilding going to be a place of relaxation? You may not need a dimmer.

I assume there is no water in this outbuilding?

I specified a dimmer just because I don't know how bright the lights will be and might want them down a touch. There will be no water or other services here. It will be mainly for storage and possibly chilling out in. Not much sign of that though.

 

[securespark]

Never give up hope!

 

[geraldthehamster]

ok, thanks for clarification. It sounds a bit of a challenge so my main task will be finding someone competent enough to do what you suggest. I like the idea though if someone's able to do it. I would be happy to reduce the door heights from 210cm to about 200cm too, but does that mean the new sole plate would be terminated at the doors/windows and that these would be sitting on the brick plinth instead? Otherwise they would be about 30cm shorter. Also, where should the acrows be positioned, because the frame is no longer exposed anywhere.

Firstly, please bear in mind that I am not a builder. Just a competent DIY-er who has built garden buildings and timber framed extensions. So if a builder comes along and tells you that this is a daft idea, listen to them, not me. I'm just telling you what I would try to do, if someone held me back and prevented me from knocking it down and starting again.

I would terminate the sole plate at the door threshold. Plant the sill of the door casing on the same DPC that the sole plate sits on. Build a step up on the outside. Make your floor slab level up to the bottom of the door sill, to allow for a floor covering. Make sure that the DPM you place under the floor slab laps up to meet the DPC all round.

Un peu comme ça:

View media item 101954
Acrows, I guess if you are doing one side at a time, place a scaffold board under the edge of the ceiling, to spread the weight, and support for 2 or 3 acrows.

 

[securespark]

Is that an ice-cream treat for the builder or a tub of screws ?

 

[efunc]

Thanks, I need to investigate further but this will certainly be an option. Trying to get someone to come out and look at it though is a bit of a challenge.

In the meantime I need to do something with the roof. Almost everyone I've approached will not even touch it without over-boarding first. Even if I pull the epdm up myself somehow it will still leave patches of thick mastic in places and any roofer will want a smooth, clean surface. I did consider 5mm ply on top, but that's just not adequate to bond a new roof material too. If I go ahead with another layer of 18mm boards my worry is the additional weight will have adverse consequences for an already compromised structure. It's probably an additional 200kg on the 3x6m structure, but it's 200kg I would prefer not to have sitting on top. Not to mention the new EPDM which may be another 50kg. Should I be concerned about this, or just go for it? Is 12mm likely to adequate, or maybe 8 or 10mm, given that these are just going to be sitting on existing 18mm boards?

 

[geraldthehamster]

You don't stick down EPDM with mastic, so hopefully they haven't. Have you tried pulling off the existing EPDM?

Without re-reading the whole thread, have we established if there is insulation in the roof?

I don't think it's going to cost significantly more to have this removed and built properly, than to have it bodged now, and built again when it's fallen over and sunk into the swamp.

 

[efunc]

The Cortex system was supplied with a thick, black, gloopy adhesive which was used to bond it down at the edges where it's stuck hard. They also used another thing, perhaps just a pva, or a waterbased glue, and seems to lift off easier. I may give it a go with the aid of a hot air gun perhaps. If I purchase a sheet of epdm and glue, flashing and trims etc I calculate it would be about £250. That ought to be a job I can do myself, but does require a clean surface first, which does worry me a bit.

The roof has that rockwool type insulation used above the plasterboard between joists I believe.

 

[geraldthehamster]

OK. If the rockwool is used like that, and there is no ventilation, in an ideal world there would be a vapour barrier (plastic sheet) underneath it behind the plasterboard. This stops moisture rising from heated air in the room and condensing in the roof structure.

Usual way to install EPDM is with contact adhesive round the edges, and a water based adhesive for the rest. The latter is fairly easy to lift. Perhaps you could scrap the mastic to get a good surface. Ultimately, if the new EPDM goes down over am irregular surface it's not going to matter, other than aesthetically maybe. As long as there is nothing to puncture it.

Yes the OSB needs to be clean. It also needs to be bone dry or you will get ripples and bubbles in the new EPDM

There are some good installation videos on Youtube, and here:

http://www.rubba-seal.co.uk/

I got my supplies from them and found them well-priced (I have no connection with the company).

 

[efunc]

Hello all, after several weeks and no tangible progress I’m coming around to the inevitable – to dismantle what has been built, prepare the groundwork and re-erect the building properly. Hopefully re-using as much of the materials as is possible. It will be difficult, not least in part because it was all banged together using random nails instead of simple screws and brackets, but the costs of proceeding with things as they stand are almost as much anyway. I have had a quote of £3,500 to do this using existing materials, which is prompting my decision, but it does concern me being so low! I imagine another £1500 in additional materials (doors, windows) on top of that, but if that can be done competently I’ll bite the bullet.

What I’m wondering is if someone could point me to some kind of guide, or checklist, of the key processes and procedures that need to be followed building a timber garden room like this. I have some idea, but only as a complete layman, so could do with some guide to cross-check the quote from the builders and any work that they end up doing. If anyone knows of an ‘idiot’s guide’ or web resource where I can follow the correct steps or plan ahead that would be great. Thanks for all the advice!

 

[Notch7]

Hello all, after several weeks and no tangible progress I’m coming around to the inevitable – to dismantle what has been built, prepare the groundwork and re-erect the building properly. Hopefully re-using as much of the materials as is possible. It will be difficult, not least in part because it was all banged together using random nails instead of simple screws and brackets, but the costs of proceeding with things as they stand are almost as much anyway. I have had a quote of £3,500 to do this using existing materials, which is prompting my decision, but it does concern me being so low! I imagine another £1500 in additional materials (doors, windows) on top of that, but if that can be done competently I’ll bite the bullet.

What I’m wondering is if someone could point me to some kind of guide, or checklist, of the key processes and procedures that need to be followed building a timber garden room like this. I have some idea, but only as a complete layman, so could do with some guide to cross-check the quote from the builders and any work that they end up doing. If anyone knows of an ‘idiot’s guide’ or web resource where I can follow the correct steps or plan ahead that would be great. Thanks for all the advice!

I would suggest getting more than one quote if possible. I know that is easier said than done as many wont want to quote on a half finished job.

Whoever you choose, ask for references, go and see some of their work. For a builder, thats a bit of an irritation for a small job, but if you explain youve been caught once and want it happening twice any reasonable tradesman would understand, you just need to approach it with polite diplomacy.

The problem you have is that many tradesman just wont be interested in such a job, so its inticing to cowboys. It sort of needs a 1 man band chippie with a labourer and a brickie mate.

Id guess its about 3 weeks work to demo, sort out brickwork, re build so price is about rightish......albeit a rough rough guestimate.

 

[ivixor]

Do it yourself! It's not that hard and you will get a lot of help here.

Also watch this entire series:

I followed that and my garden room is up and looking not too shabby.

 

[efunc]

I would suggest getting more than one quote if possible. I know that is easier said than done as many wont want to quote on a half finished job.
Id guess its about 3 weeks work to demo, sort out brickwork, re build so price is about rightish......albeit a rough rough guestimate.

Thanks for the perspective. You're not wrong, I've had a number of reputable firms round with NFRC credentials and big project work, etc, and none of them come back for a second visit after feasting their eyes on the work. Or they drop me an email later tripling their original quote. That leaves it open to the smaller, less accountable one-man-bands. Many of these aren't cowboys at all, but it's much harder to get a feel for who's right. Like you say, viewing other work is key. The reason I was suspicious of the £3500 quote was that others have said they would want about £9000 to build something, but £3500 trying to salvage existing material really does seem very appealing if realistic. I can't help thinking it would cost more, not less to try to dismantle and salvage the existing materials and organise them whilst site clearence and re-construction took place. Sounds a bit of a nightmare. I imagine only about 60% of it will be usable and I'll still need to shell out a fair bit more.

My priority though will be to get the base right. I've researched how people build these and most seem to opt for pile foundations, or a high slab with timber subfloor perched on top. Whilst this would be more than adequate for my building with 2.5m x 3.5m footprint and 2.5 x 3m overhang, I really find them quite ugly aesthetically, looking like temporary structures. Plus the underside would be a haven for foxes, rats and rodents. I'm really looking for some way to close off the bottom, and perhaps this is achieved with timber siding or something to mask the void? I much prefer the brick base posted above by garaldthehamster, but have found no examples of garden rooms built like this for some reason. Possibly because it's considered overkill?

 

[efunc]

Do it yourself! It's not that hard and you will get a lot of help here.

Also watch this entire series:

I followed that and my garden room is up and looking not too shabby.

Thanks, that's great to hear about your success! I work FT and also have other responsibilities too so don't possess the time/skills/tools/transport/etc to do it all myself, but perfectly happy to chip in in support if someone else takes on the task. I actually know of Alistair as he's a couple of miles down the road from me. He was going to pop round to have a look but has been great in offering advice too. The budgets for these things from the established companies easily tops £15k or more, so doing something myself bespoke definitely has it's advantages. Just look at some of these examples:

https://www.crusoegardenrooms.co.uk/
https://apododesigns.co.uk/example-designs-pricing