Garage floor

[RMS]

Hi all

I am looking to convert my garage. What I mean is make it a usable space, keep the garage door which is insulated so I can easily put it back as a garage in the future if need be.

I have knocked a wall down between my garage and house. There is a pitched roof above all this tied into the house wall. We had this put on when we extended the house.

The floor falls down towards the garage door and there are two floor levels now. I want to raise the floor and put insulation in. What do you guys think is the best option considering the points above.

The depth between my exisiting house floor and the lower floor is 190mm and 120mm to the higher floor in the garage.

Sorry about the long post.

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• RMS
• 20 Jul 2013
• 1

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• RMS
• 20 Jul 2013
• 1

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• RMS
• 20 Jul 2013
• 1

 

[pred]

I may have read this wrong but where a garage joins a house you must have a step of i think it is 6" down into the garage, the reason being inflammable liquids give off a heavy vapour that spreads like a liquid, hence you must have a step up into the house, building regs!

 

[RMS]

But it will be a habitable space and not a garage.

That's why I won't something on the floor that can be easily converted back into a garage. Eg achieving the step into the garage.

 

[^woody^]

Timber floor

 

[RMS]

If I go for timber, should I get pressure treated? I will be putting a DPC down.

Also where do I stand with ventilation. The front of the garage will be raised off the floor to level the floor up so this would allow ventilation. Would this be acceptable?

 

[pred]

But it will be a habitable space and not a garage.

That's why I won't something on the floor that can be easily converted back into a garage. Eg achieving the step into the garage.

Sorry I'm a bit slow today, the step, will it be down into the garage?

As in the garage floor 6" lower than the house floor?

 

[^woody^]

If I go for timber, should I get pressure treated? I will be putting a DPC down.

Also where do I stand with ventilation. The front of the garage will be raised off the floor to level the floor up so this would allow ventilation. Would this be acceptable?

You don't need treated timber.

You don't have to ventilate this type of floor. Just make sure that either the whole void is filled with any insulation, or the cold floor is covered with sheet insulation (not quilt) and any air gap is above it

 

[RMS]

The space I have would allow 4 x 2 timber for the floor. These would span just over 4m. How would you go about supporting the floor considering the floor slopes down towards the front of the garage. Is it a case of of packing the floor on top of the dpm?

I could fix one side of the floor to the house wall where the floor is lower.

 

[^woody^]

The easiest thing to do is fix timber level to the sides of the garage, and then hang the joists off these with steel speedy hangers

Lay the DPM on the floor (knock off and sharp bumps) and up the wall a bit, behind the timbers fixed to the wall. If the joists are bouncy, then drop a nogging down the centre which rests on the slab

 

[RMS]

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• RMS
• 22 Jul 2013
• 1

Okay, fixing a level timber to the house side is fine but on the other external wall there are brick pillars. See picture. There is three of these, should I frame it in sections between these or cut out a slot for the wood to sit against the wall and span the full length.

Will it be okay to fix the wood to the external wall with the dpm behind?

 

[^woody^]

Work it so that there is no joist on the pier. It's OK regarding the DPM and fixing to external wall, but you should lap the vertical wall membrane over it (wall membrane behind the DPM upstand)

 

[RMS]

It's been a while......but ive completed the floor now.

As explained, dpm, joist hangers, noggins resting on concrete and plenty of packers glued in place. Filled whole void with wool type insulation. Should I have put a vapour barrier on top of the joists?

For the walls I will be using 4 x 2 screwed to floor and ceiling. Leaving a cavity. The stud work will be about 50mm in front of piers allowing for insulation. Then a vapour barrier can be fitted to the front. Does this sound okay? Do I need a vapour barrier on the back side?

The ceiling is already boarded and plastered from when the pitched roof was fitted above the garage, should this have vapour barrier fitted? I will be installing insulation above the ceiling

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• RMS
• 4 Jan 2014
• 1