Garage conversions

[blue matt]

I Have done many garage conversions ( both years ago in Barry and then down here ) I guess with the Bed, Kitchen, Toilet its going to be a " granny flat " or a " independent son / daughter place " , for this you will 100% need planning permission, the toilet and bed will dictate that

Now, I always ask potential clients at the 1st meeting what they want out of the conversion, plenty just want a Home office, some want a man cave, now this might include a toilet / small kitchen, If they are ok with themselves " bending the planning rules " it makes it alot easier to do, they create a " store room " ( call it what you will ) and convert that, yes that " store room shoudlnt have a kitchen or toilet , but who the hell will know ? ? ? going down the legit planning permission will add a few K onto the price right at the start

By avoiding planning and building regs ( now i am not talking of unsafe work, Electrical work will be done by a sparky and signed of ( if major ) though most garages will have lighting and a double socket on its own MCB, so not massive to extend the electrical ring ) will make the job alot easier and flexible, not to mention cheaper

as for the design,

I will lay down some DPM, on top of that lay either use 100mm or 75mm X 50mm " ( more often than not C16 CLS ) floor joists, with 50mm PIR board ( celotex / kingspan are 2 fairly common brands ) between the joists, then lay chipboard floorboards down

i normally use CLS timber to create a stud wall around the walls, fill the gaps of the stud with 50mm PIR if the garage as block / brick piers, i fit the studwork infront of them and fill the void behind it with 50mm PIR, , thats 100mm in total, if space is a premium, i fit the stud work between the piers and just use the 50mm between the CLS stud work, now i know that wouldnt be good enough for building control
staple a vapour barrier to the stud work and then plasterboard

As for the flat roof, you will be able to get plenty of PIR between the roof joists then plaster board, of course if the ceiling is plasterboarded, you will need to rip it down, once again, a vapour barrier and plasterboard

Wall mounted oil filled rads are great for keeping the room warm, low cost to run, looks nice, i have fitted underfloor heating ( warmup is a fairly decent brand ) in the past aswell, but thats a personal choice, maybe use both

I honestly find 50mm PIR warm enough, of course you can go 75 / 80mm ( i have 80mm in the ceiling of my new shed ) I am happy to go with 50mm for the floor and walls, then 80 - 100 for the roof

the big question is how much bending of the rules are you happy with, keep in mind if you do come to sell the house, you will only be able to sell it as a house with a " garage / shed / store room " and most likely have to pay for a £150 Indemnity insurance to cover the building

[Optimistic Nick]

as for the design,

I will lay down some DPM, on top of that lay either use 100mm or 75mm X 50mm " ( more often than not C16 CLS ) floor joists, with 50mm PIR board ( celotex / kingspan are 2 fairly common brands ) between the joists, then lay chipboard floorboards down

Ignoring the obvious (and acknowledged) BC and PP issues here, I can't quite get my head around this. What are these 75x50 CLS "joists" bearing on? Surely they cannot be spanning anything so presumably these are actually resting on an existing slab? If so - I can see the logic of the DPM but why bother with the joists at all? Why not just float the P5 on the PIR? And to be honest at 50mm for floor insulation- why bother at all? The heat saving through the floor will be negligible, but surely most of the buildings you are doing this to are limited to 2.5m height and so even a 63mm loss of headroom is sub-optimal?

[blue matt]

Ignoring the obvious (and acknowledged) BC and PP issues here, I can't quite get my head around this. What are these 75x50 CLS "joists" bearing on? Surely they cannot be spanning anything so presumably these are actually resting on an existing slab? If so - I can see the logic of the DPM but why bother with the joists at all? Why not just float the P5 on the PIR? And to be honest at 50mm for floor insulation- why bother at all? The heat saving through the floor will be negligible, but surely most of the buildings you are doing this to are limited to 2.5m height and so even a 63mm loss of headroom is sub-optimal?

you are right they just sit on the slab, so no span / load bearing issues, 2 reasons for doing this

1. i have always done it like that, in the 90's people used to use polystyrene jablite batts

2., i run 32mm waste pipe from corner to corner under the floor ( i understand the required fall will not be achieved ), this is done for 2 reasons, if a client wants to put a washing machine in the corner, they can , if they want to run cables at a extra date, its easy to do, i just up turn the 32mm waste pipe and it lives behind the stud wall


Now the reason why i put insulation in, people like the idea of it, we are sold the more the better, a nice insulated floor ( despite the heat loss on the floor being very little )

Most garages are higher that 2.5M as they would either have been built with the house or needed PP to be built, i would guess that the height is most often than not 3M high inside

[goats]

I Have done many garage conversions ( both years ago in Barry and then down here ) I guess with the Bed, Kitchen, Toilet its going to be a " granny flat " or a " independent son / daughter place " , for this you will 100% need planning permission, the toilet and bed will dictate that

Now, I always ask potential clients at the 1st meeting what they want out of the conversion, plenty just want a Home office, some want a man cave, now this might include a toilet / small kitchen, If they are ok with themselves " bending the planning rules " it makes it alot easier to do, they create a " store room " ( call it what you will ) and convert that, yes that " store room shoudlnt have a kitchen or toilet , but who the hell will know ? ? ? going down the legit planning permission will add a few K onto the price right at the start

By avoiding planning and building regs ( now i am not talking of unsafe work, Electrical work will be done by a sparky and signed of ( if major ) though most garages will have lighting and a double socket on its own MCB, so not massive to extend the electrical ring ) will make the job alot easier and flexible, not to mention cheaper

as for the design,

I will lay down some DPM, on top of that lay either use 100mm or 75mm X 50mm " ( more often than not C16 CLS ) floor joists, with 50mm PIR board ( celotex / kingspan are 2 fairly common brands ) between the joists, then lay chipboard floorboards down

i normally use CLS timber to create a stud wall around the walls, fill the gaps of the stud with 50mm PIR if the garage as block / brick piers, i fit the studwork infront of them and fill the void behind it with 50mm PIR, , thats 100mm in total, if space is a premium, i fit the stud work between the piers and just use the 50mm between the CLS stud work, now i know that wouldnt be good enough for building control
staple a vapour barrier to the stud work and then plasterboard

As for the flat roof, you will be able to get plenty of PIR between the roof joists then plaster board, of course if the ceiling is plasterboarded, you will need to rip it down, once again, a vapour barrier and plasterboard

Wall mounted oil filled rads are great for keeping the room warm, low cost to run, looks nice, i have fitted underfloor heating ( warmup is a fairly decent brand ) in the past aswell, but thats a personal choice, maybe use both

I honestly find 50mm PIR warm enough, of course you can go 75 / 80mm ( i have 80mm in the ceiling of my new shed ) I am happy to go with 50mm for the floor and walls, then 80 - 100 for the roof

the big question is how much bending of the rules are you happy with, keep in mind if you do come to sell the house, you will only be able to sell it as a house with a " garage / shed / store room " and most likely have to pay for a £150 Indemnity insurance to cover the building

Know of people who lay the foundations for waste but then cover it up, leave it as is for a few years until they think planning won’t be interested, then put in the wc etc....adding a kitchen is simple enough....it’s a risk though, only takes one neighbour to report someone is living in it and it’s all over.

[Vindec]

Know of people who lay the foundations for waste but then cover it up, leave it as is for a few years until they think planning won’t be interested, then put in the wc etc....adding a kitchen is simple enough....it’s a risk though, only takes one neighbour to report someone is living in it and it’s all over.

But what happens if the house is put up for sale and the first question the proposed buyer's solicitor will ask is where is the documentation for planning permission and building regs?

It's best to be truthful from the from the outset as decisions taken now could have future consequences.

[blue matt]

Know of people who lay the foundations for waste but then cover it up, leave it as is for a few years until they think planning won’t be interested, then put in the wc etc....adding a kitchen is simple enough....it’s a risk though, only takes one neighbour to report someone is living in it and it’s all over.

Ive known people do that, they know in 6 - 12 months time granny might be moving in, so just run the waste and fit a toilet if they do, even known someone fit a washing machine in the corner of the room, so the waste and pipes are run

talking of neighbours, i know of someone who was convinced his next door neighbour would grass him up, so as he was in the planning stage ( not planning permission ) he moaned to the guy about the cost of architects and the cost of planning and said he had just been charged this and that for the plans and to submit them, the power of persuasion

[dml1954]

Know of people who lay the foundations for waste but then cover it up, leave it as is for a few years until they think planning won’t be interested, then put in the wc etc....adding a kitchen is simple enough....it’s a risk though, only takes one neighbour to report someone is living in it and it’s all over.

Thats ok until you want to sell, even five or ten years down the line and then the first thing the buyers solicitors will do is a local authority search and the second thing is tell their clients not to buy it !

[blue matt]

Thats ok until you want to sell, even five or ten years down the line and then the first thing the buyers solicitors will do is a local authority search and the second thing is tell their clients not to buy it !

or its sold as a " posh garage " and you have to pay for a £150 Indemnity insurance to cover the building

[goats]

Thats ok until you want to sell, even five or ten years down the line and then the first thing the buyers solicitors will do is a local authority search and the second thing is tell their clients not to buy it !

Exactly, if you are going to do it....don’t ever plan to move.