Big jim’s Garage conversion and layout thread

[big jim]

Ordered the wood for delivery this Wednesday, got it from a local supplier, same family firm who I bought all the garden landscaping from over the last couple of years so I got a good price delivered and a bit of a discount too (and I like to keep it local)

 

I thought while I wait for the door to be removed and bi-folds fitted I can at least crack on with battening out inside

 

Bought 25 x 4.8 m lengths and a 3 x 3.5m lengths of 4x2 (100x47), I’m hoping my calculations are right! I’ve over ordered by a few lengths which should make up the internal stud wall too, just got to go screwfix and get a big bucket of 4”’nails tomorrow in preparation, I’ve got a good circular saw which should make life a lot simpler too

 

I’m going to build the framework up loose then when ready to fit add the dampcourse membraine to the rear of the woodwork and below and screw it to the walls via the internal brick pillars so I’m not drilling through to the external wall

 

Hopefully the door issue can be sorted next week too, I’m reluctant to remove the garage door myself as it’s sprung loaded, I think it’s just a case of winding back the springs to release the tension on the cable then I can safely remove it panel by panel, of course it needs to be done the same day as the bi-folds being fitted as I don’t want to leave the garage open (even though it will be empty)

 

Unfortunatly as I’m now ready to do the battening I need to fully empty the garage of the last of the things I’ve kept such as bikes, jet wash, garden furniture etc which means the stuff in there needs to go in the shed so I’m going to have to pack up the stock from the layout, cut the track I’d fixed across the (non) removable section and take it out for good rendering the existing layout kaput!

[big jim]

Big pile of wood

 

Cut a few lengths up for the first ‘bay’, not nailed anything in place yet, 400mm centres between each upright as per the building inspectors spec, one gap will be 150mm though

 

Got to get the fuse box removed from the wall to get one upright in place

 

The board in this pic is roughly where the partition wall will be when complete

 

Looking at flooring in B&Q too, can get 3 packs of these for £21 so £84 to do the whole floor, probably cheaper to buy big sheets of t+g ply though

 

And maybe put some of this polystyrene sheeting under it, between 2’ Battens

[chris p bacon]

Use 8' x 2' sheets of Chipboard T &G for the flooring and glue the joints together. You don't need to fix battens down, just lay the insulation down with the chipboard on top.  It's a floating floor.

My own railway room is done that way although there is 150mm of insulation underneath ( this was more to do with differing floor levels between front & back of house) and there is no movement so perfectly suitable.

[teaky]

After your discussions with the BCOs have you decided not to have an air gap?  Or are you not filling that 100mm frame to the full depth?

 

If you are putting in insulation to less than the full depth, then I recommend you fasten a few small (50mm or 25mm thick, depending on the air gap you require) treated battens or even scraps of treated timber to the wall in the spaces so that when you push the insulation home it will reach a stop point.  Insulation should be a firm, push fit and if you push it too far in it's a beggar to pull back out again if you're on the last piece.

 

I'd also echo Chris P Bacon's advice regarding flooring.  I can't tell for certain but those B&Q panels look like the packs sold for loft storage areas.  If they are then they do not meet Building Regulations for a proper floor because they are not moisture resistant.  They may also not have tongued & grooved ends, just sides.  Buy the proper stuff: 2400mm x 600mm x 18mm (usually coloured green like your treated timber).

 

One further question.  Are you just building the partition wall in timber?  I ask because when I converted our garage I created a habitable room at the back accessed via the personnel door and a storage space across the front accessed via the up-and-over door.  The partition wall was constructed from treated timber in the standard fashion, filled with PIR insulation and lined on the storage side with fire proof plasterboard (the room side was in standard plasterboard like the rest of the room).  The whole lot sat on a two (engineering) brick high mini wall with a damp proof course on top tied in to the DPC of the existing garage.  This was all as advised by the BCO.

[big jim]

it will have 75mm insulation, 25mm airgap, membraine to go on the rear too when i nail it all up, also got the thin strup of DPC to go under the wood as i fix it in place

 

the 100mm insulation i mentioned previously will be whats going in the celing void with 25mm plasterboard/insulation below beam level (25mm airgap above the insulation)

 

i was going to just run smaller nails into the insulation to keep it in place from the sides but i'm liking your idea of 25mm strip of wood to the rear instead

 

yes the flooring in the pic is attic panels, i didnt realise they wouldnt be up to code, i had semi decided on the big sheets anyway as it should be cheaper and more solid than having numerous joints

 

for the partition wall i was planning on using the 4x2 across the width of the garage lain on the floor (on the dpc strip) then build it up as per the side battens, 400mm gaps between uprights, filled with insulation etc, door frame kit from B&Q, standard plasterboard both sides, when the flooring is ready to be fitted ill then add a futher dpc/visqueen sheet nailed to the bottom battens all round and sit the polystyrene insulation on top of that then obviously the ply on that too

Edited May 17, 2018 by big jim

[teaky]

That makes sense now.  Thanks for clarifying.

 

I've added a few more comments below.

 

it will have 75mm insulation, 25mm airgap, membraine to go on the rear too when i nail it all up, also got the thin strup of DPC to go under the wood as i fix it in place

the 100mm insulation i mentioned previously will be whats going in the celing void with 25mm plasterboard/insulation below beam level (25mm airgap above the insulation)

i was going to just run smaller nails into the insulation to keep it in place from the sides but i'm liking your idea of 25mm strip of wood to the rear instead
With the battens there to push up against, you shouldn't need anything further to hold the insulation in place.  You should have to push or smack it firmly onto place.  Small gaps have a significant effect on the performance of the insulation so aim for as few as possible and plug any you do get with slivers of insulation (much quicker and easier than it sounds).

 

yes the flooring in the pic is attic panels, i didnt realise they wouldnt be up to code, i had semi decided on the big sheets anyway as it should be cheaper and more solid than having numerous joints

Don't forget to glue the joints with waterproof adhesive as you put the panels in too.

for the partition wall i was planning on using the 4x2 across the width of the garage lain on the floor (on the dpc strip) then build it up as per the side battens, 400mm gaps between uprights, filled with insulation etc, door frame kit from B&Q, standard plasterboard both sides, when the flooring is ready to be fitted ill then add a futher dpc/visqueen sheet nailed to the bottom battens all round and sit the polystyrene insulation on top of that then obviously the ply on that too

I think the reason the BCO advised me to put in the brick base and fire rated plasterboard was because I intended to continue to use the front of the garage for the usual "garage" stuff, so there are a few paints, white spirit, oil, grease, pieces of timber etc. all amounting to a fire hazard in the usual way.  Garages are normally built with floors below the level of living accommodation and with a slight slope away from the house/personnel door which ensures any spillages take the safest route.  I don't know if this applies to you but if it does, it is a very simple bit of bricklaying since it is largely out of sight when finished and accounting for any slight slope can be done by laying fractionally thicker mortar courses towards one end.

 

[big jim]

But more woodwork done, took out the loose frame and nailed it all up

 

And back in place as far as I could, need to get the electric box and plug socket moved first

 

I then chopped some of the rear shelving back so I could carry on with the back panel

 

And loosely in place, again got to get it out and nail it up etc

 

Then as I was in the mood for it I carried on with the wall on the opposite side of the garage behind the freezer

 

And the bit under the window

 

 

That’s really as far as I can get panelling wise until I remove the last of the stuff from the garage into the shed to get to the rear wall, (I may well do that tomorrow but it also means the existing layout will not be able to be used and I can’t yet bring myself to face that!)

[doilum]

Big pile of wood

Cut a few lengths up for the first ‘bay’, not nailed anything in place yet, 400mm centres between each upright as per the building inspectors spec, one gap will be 150mm though

Got to get the fuse box removed from the wall to get one upright in place

The board in this pic is roughly where the partition wall will be when complete

Looking at flooring in B&Q too, can get 3 packs of these for £21 so £84 to do the whole floor, probably cheaper to buy big sheets of t+g ply though

And maybe put some of this polystyrene sheeting under it, between 2’ Battens

Too late to help you, but for anyone contemplating this conversion, I have always been a fan of the "green" chipboard as recommended for bathrooms and kitchens. I also painted the underside with bitumen paint. This a left over from attempting to tank a sectional concrete garage which lay partly below ground level. 10 years on, the modelling area has always been bone dry.

[big jim]

Not too late, not bought the flooring yet, I’m gonna go for the big green chipboard panels having had a look into it

[Enterprisingwestern]

Probably a tad late, but you could do worse than wrap some damp proof membrane under and behind the wall battens to stop damp and termites penetrating the wood.

 

Mike.

[big jim]

if you read the descriptions a few posts up you will see they are loosely fitted (not actually nailed yet) ready to be refitted with the membrane to the rear and underside of the battens, its actually part of the spec from the building regs man that they have to be fitted

[Enterprisingwestern]

if you read the descriptions a few posts up you will see they are loosely fitted (not actually nailed yet) ready to be refitted with the membrane to the rear and underside of the battens, its actually part of the spec from the building regs man that they have to be fitted

 

I read the thread, honest. Must have missed that bit, apologies.

 

Mike.

[big jim]

Not done anything for the last month while finances are built back up for the next stage

 

Monday morning Im having the garage door removed (me and my dad doing that) and I’ve got someone in to do the bi-fold doors fitting

 

While he is doing the doors we are going to get the wooden frames I’ve already cut back out and nail them up, refit them with the breathable membrane as well as making up the final 2 panels, possibly get the framing in for the internal wall too, depends what I can get done before work!

 

Watch this space

[big jim]

And here we go

 

First up one of the stud walls with the tyvek membrane fitted, were hoping to do a couple more but had one of those days, MOT on the car (which it failed) and other running around getting bits and bobs

 

And here is the bi-fold door which was a swine to get to fit perfectly but we got there in the end

 

 

Utility room access

 

Fully open into workbench area

 

Need to add one piece of facia board to the wood above the door, then guttering back up and on to the inside

Edited June 18, 2018 by big jim

[shanks522]

Looking like a great space Jim! i'm not envious at all.......

 

Graham.

[big T]

Good progress Jim!

 

Any ideas on trackplans for your layout?

 

Trev

[big jim]

Crikey, give a chance to build the space first!!

 

TBH, the only thing I have defiantly decided on layout wise is it will have helix to lots of lower level storage sidings so I can get all my locos and stock out of their storage boxes and run them rather than having to choose stuff to put on the layout and swap them in and out as I do now due to lack of layout space, I may even put display cabinets on the walls for locos so I can swap them in and out and keep them away from dust when not being used

[fishytrains]

Nice to see the progress you have made so far.

 

Mike

[big jim]

Picked up some insulation off eBay which I went and picked up yesterday, unfortunatly the car with fold down seats failed its MOT on Monday so I had to take the phaeton which doesn’t have so I had to chop the big 8x4 sheet down to get it home, there is still some at the guys house that I couldn’t get in that illnahve to collect on Friday, luckily he’s not too far away!

 

Got 75mm and 100mm thick pieces off him

 

Decided to fit up the 100mm stuff into the roof space

 

25mm airgap between the insulation and roof

 

Gonna need at least another 6 sheets to complete the roof

[teaky]

A few comments if I may Jim.

 

The insulation is at its most effective when there are no gaps.  I appreciate you had to cut the sheets off site and you've got pretty close to size.  If you saw some thin wedges from the end of one of the sheets yet to be installed such that the thicker end of the wedge is a few mm wider than the gap you are aiming to plug, you can then push them into place and any insulation protruding below the main sheets can be sliced off flush.  (You could saw a wedge from the length but it is easier to work with shorter pieces.)  This is much easier to do than to describe.

 

Unless you are intending to put another layer of insulation below the rafters, the joints along all sides the insulation should be sealed with aluminium tape to restore the integrity of the foil vapour control layer.  You can buy this tape from lots of sources but it is often cheaper online.  Shop around a little though because I have found it varies from less than £3 to more than £10 for the 50m rolls and often it is the same manufacturer.

 

Does the air gap you've left connect to the outside world in any way?  You're aiming to prevent moisture build up but it does need some air flow to help it evaporate.  Perhaps someone more knowledgeable can confirm here, but an air gap at a brick wall is OK because the brick itself is sufficiently permeable to breath but for a roof like yours you are sealing from below with insulation and from above with a waterproof top layer.  For the loft conversion that I still haven't finished, the BCO was keen to ensure the ventilation requirements were adequate and I have vents at eaves and ridge.  I'm not suggesting you need anything like that but I do think there needs to be something to ventilate the space.

[chris p bacon]

50mm round vents popped into each rafter space at the fascia ends will vent it.

 

And as Teaky says wedge them and tape them.

[teaky]

These are slightly larger than chris p bacon recommends but I needed a different size.

 

I used these for the soffits: https://www.screwfix.com/p/circular-soffit-vent-white-70mm-10-pack/68936#_=p

 

Some cheaper ones: https://www.toolstation.com/shop/p59214

 

I only opted for the Screwfix ones because the cross braces looked a little stronger but it probably doesn't matter.

 

They weren't available at the time but I'd probably have bought these instead simply because they're a little cheaper and you can buy the exact number you need: https://www.wickes.co.uk/Circular-Soffit-Vent-White/p/119650

 

Don't forget to buy or borrow a hole saw of the correct diameter if you don't already have one.

[big jim]

They are wedged in and a tighter fit at the top as the cuts weren’t exactly in a straight line though the insulation

 

I’ve still got to add the plasterboard with an extra 25mm of insulation below rafter level yet so hopefully that will help to seal things further

 

Regard the air gap, yes it does go ‘to outdoors’ to get an airflow, I’ll get a pic later but basically the lip of the Grp garage roof isn’t flush to the walls either side, it is about 30mm away from the wall and the rafters are also slightly higher than the top of the brickwork, again 30mm or so

Edited June 21, 2018 by big jim

[big jim]

Bit more done today and a visit from the building inspector to check we were doing alright

 

All the wooden framing in place bar one section that will require the consumer unit moving

 

Tyvek membrane on the rear

 

Ready for the insulation in front

 

Had yet another inspector turn up today who told me i was breng overkill with the 75mm wall insulation and I only required 50mm stuff which is not what the last guy said, anyway I’m going to use the 75mm up (only have 5 panels left) and switch to 50mm for the rest of the build as it’s pretty much £15 a sheet cheaper than the 75mm stuff

[Richard_A]

Building inspectors can contradict each other so much, you'd think they'd talk to each other, unless you get the same one all job, you can get some conflicting advice.