Floor options to raise 30cm

[AD2001]

I'm looking to add a small utility room off my internal garage. Kitchen door opens directly in to future utility room but it's a 30cm drop to garage floor.

It will only be a 2.25m by 1.25m utility (as saving rest of garage for a future office with it's own door from hallway).

As it's only 2x1m, can I just put some dpm down, then use timber to level it up to kitchen floor, filling the floor void full of insulation so no air circulation issues?

I'm looking to do this mostly myself to save costs so think that would be an easier floor option compared to laying a dwarf wall with joists etc.

Also my woodwork skills are probably a lot stronger than bricklaying.

Thanks for any advise on this

 

[thomp1983]

Google floating floors, if you laid 200mm pir with 75mm pir on top then laid 22mm t+g chipboard on top of the pir your new room would end up 3mm below your current floor level which you will be able to take up with the relevant underlay for your flooring finish

 

[AD2001]

No issues of a washing machine/ dryer being on floating floor?

 

[23vc]

No, it’s a valid floor design. It’d still have chipboard or whatever on top of the insulation and whatever floor covering on top of that

 

[Deluks]

If your washing machine is particularly jumpy on full speed, you could use 38mm chipboard mezzanine flooring, to make things a bit more solid underfoot.
To mitigate the effects of a leak, there is also 22mm cement board flooring to consider.

Could also use screed over insulation.

 

[freddiemercurystwin]

EPS + plywood would be my solution.

 

[williamglossop]

Why not do a suspended timber floor and insulate between the joist? Wall plates on 2 opposing walls, then joist hangers and joists. Leave a space under the joists for air to circulate and fit a cple air bricks.