New suspended floor garage conversion

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I need to build a suspended timber floor, using 8x2 c24 treated timber in the garage.

Given that the garage is not level

I was planning on tackling it as follows:

Fix one of the wall plates to the wall using 140mm rawlbolts with a 30mm drop and then hang one joist so i can then determine and get an exact level of where to fix the second wall plate on the opposite end

Is this the best way to do it?

Any pointers or tips on how I can ensure i have a level floor and ensure there is a drop of 30mm end to end?

The 30mm drop is to account for the chipboard flooring and laminate flooring which will then bring me to the finished floor
 
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ash1212002, good evening.

I assume?? that there is a personnel door accessing the garage? [possibly] from the house???

If so how about considering starting at the door, and using a spirit level and a timber straight edge you very carefully mark a level around the area, but?? go left and right from the access door and meet up [probably] in a corner, but at the "closing" of the left and right runs around the room [in the corner] make sure you watch the spirit level, not what you want to see at the closing of the marking.

By the above, you will have something to "Aim For" as you are fixing the wall plates? and whilst fixing the wall plates keep on checking the levels!!

As an aside? have you considered a DPM of some sort and what about insulation?? or a DPC between the wall plate and the walls?

Ken
 
ash1212002, good evening.

I assume?? that there is a personnel door accessing the garage? [possibly] from the house???

If so how about considering starting at the door, and using a spirit level and a timber straight edge you very carefully mark a level around the area, but?? go left and right from the access door and meet up [probably] in a corner, but at the "closing" of the left and right runs around the room [in the corner] make sure you watch the spirit level, not what you want to see at the closing of the marking.

By the above, you will have something to "Aim For" as you are fixing the wall plates? and whilst fixing the wall plates keep on checking the levels!!

As an aside? have you considered a DPM of some sort and what about insulation?? or a DPC between the wall plate and the walls?

Ken

Evening Ken,

Thank you for your response.

The garage opening has been bricked up with a window, the opposite end I've taken the wall out which leads to the kitchen.

The kitchen floor level is higher than the garage floor, so what i had done was mark down 30mm on the garage floor level and drew a straight line into the corner and then across to where the wall plate will be fixed

Hope that makes sense

Re Dpc i will be placing this behind the wall plates :)

Spoke to the BCO officer no need for dpm, insulation he suggested 150mm jablite in between the 400mm centres. Would have preferred mineral wool for cost savings but advised it'll have to be 175mm! to achieve the necessary U values
 
I'd be inclined to mark a level line (datum) around the whole garage at a practical working height of say 1m, and then measure down to get your floor level. Much easier and less prone to errors.

I can't understand the need to put the floor in out of level though. It will be noticable.

Quilt insulation will be easier to fit, less messy and better than polystyrene. If the joists are 200 deep then use 200mm of it.
 
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I'd be inclined to mark a level line (datum) around the whole garage at a practical working height of say 1m, and then measure down to get your floor level. Much easier and less prone to errors.

I can't understand the need to put the floor in out of level though. It will be noticable.

Quilt insulation will be easier to fit, less messy and better than polystyrene. If the joists are 200 deep then use 200mm of it.


My intention is definitely to get the floor level! Confused with you second sentence

Quilt insulation, is that the official name of the product? I'm sure the BCO didn't suggest this! Will definitely be looking at this instead!

Cheers!
 
o_O

Anyway quilt insulation is mineral wool or rockwool or dritherm and the like

Ah ok lol

The quilt insulation, from doing a quick google search comes in a large roll, can it be cut down to size to fit in between the 400 centres of the joists?
 
As woody above, if you run a "Datum" line around the proposed room you can then use a [say] one meter length of timber to determine where the top of the wall plate is to be fixed, as an aside using this "Datum" method is an indusrty standard, because the "Datum" can be used for other functions, in construction it can also be used to fix the height of the ceiling, door standards Etc.

As for the "Glass Wool" floor insulation this material is generally suspended using a plastic mesh. between the joists.

Ken
 
I asked the BCO if i could use mineral/glass wool, they advised if i go down this route it'll have to be 270mm! alternatively they suggested 125mm jablite
 
The target u-value will be 0.25 W/m2K and that will be 150mm rockwool, and something similar for fibreglass (ie Dritherm)

270mm is for lofts!
 
Or where a minimum value needs to be achieved. Would the fact that the insulation is not continuous (floor joists interrupt continuity) have some bearing of between insulation only?
As its a conversion, its a lower standard .... best endeavours and all that.
 
I did think 270mm is excessive for a suspended timber floor, will double check with building control again in the coming days once the floor is up and report back

Thanks all
 
I have another question which has come to mind..

Should i use noggins 8x2 or herringbone struts?

How many should i fit?

The area is 3.60 x 4.80 metres
 
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