garage floor meeting outside ground

[Sandbags89]

Hi all,

been slowly plodding along with a DIY double garage in my back garden. Getting ready to pour the concrete floor now that the weathers finally improved.
Garage backs on to a concrete access road. I was just planning to throw down the dpm and rebar and pour and level the concrete all the way up to the access road, with either a slight slope or lip where they meet to avoid water running into the garage during heavy rain. The garage door is going to be mounted on the internal wall face, so it the floor will run through to the other side.
I'm now worried that any rainfall onto the outside portion of the garage floor will absorb and make its way back underneath the roller door. There is a house few doors down that recently done a garage and they did the concrete slab with just a lip, but still not confident, so please advise.

Hopefully I made sense with my question, attached a couple images to help

Measurements if useful:

approx 7mx6m garage
built with single skin dense blocks
garage door opening 4m

many thanks

 

[Sandbags89]

some neighbours garages, that was pretty much how I planned doing it. Will this be fine and i'm overthinking it?

 

[freddiemercurystwin]

Kinda depends what the rain does in the the road when you get a downpour, but a small lip like they've done and then say a 15mm fall down to it from the door would seem to be prudent.

 

[Sandbags89]

water doesn't really pool there or anything, not that I've notices. So I don't have to worry about it absorbing water and travelling back into the garage?

 

[freddiemercurystwin]

Not really, it's a garage yes? Unless you separate the inside concrete from the outside floor with a vertical dpm or other physical barrier then you can't really guarantee a totally dry floor on the inside behind the door. You're overthinking it.

 

[Sandbags89]

thanks Freddie

 

[Old Salt]

Garage floor should have a gentle slope from back to front so that any fluid spills will drain out of the garage. This will also aid you in keeping rain out.

 

[^woody^]

A row of blue bricks on edge in strong mortar, or a strip of strong dense concrete, well consolidated and trowelled smooth.

As you have an edge there, you could insert a strip of DPC, if the edge will be covered by the door