Laying new concrete over old down side entrance of house

davkav

About two years ago I built a glorified lean-to (garage) on the side of my house where I store a classic car and have built a workbench. The area is secured with doors front and back so we have taken to calling it the garage.

The side of the house that the lean-to is covering has two separate slabs of concrete poured from when the house was built. See photo below:





I'm hoping to pour new concrete to create a new smooth floor for the garage and to prevent rain water from running through it, which happens during heavy rain. There are two AJs and two rain water drains in the area that would need to be extended up if it were to be done.

My questions are as follows:
Are there AJ extenders available to allow the floor to be raised?
Would laying DPC before pouring help with some condensation issues in the garage?
How thick would the concrete need to be?
Is this a feasible idea?


I don't to want to go too mad building a proper garage just yet, as we are in discussions (the wife and I) about whether or not to build an extension. If we do go ahead it will be 2/3 years down the line anyway.

GreeBo

where does the rain come from ?
From the first pic it looks like there is maybe no flashing where the roof meets the house? Is the water just running down the wall of the house or you do think its coming in under the door etc?

davkav

Ah, that was a work in progress shot. Flashing has been added and is water proof. Gutters have also been ran along the perimeter wall to prevent water running back on the inside of the wall.

The boiler has also been moved to the rear of the garage and the flue extended up through and above the lean-to roof.

The rain water comes under the front or back doors depending on which way the wind is blowing.

Ronney

To stop water running through would you consider just putting an Aco Channel across the door threshold?

Is breaking out the existing not an option or considered too much work?

Yes you can get extender rings for AJ's and Gullies.

Footpaths would have a 100mm min concrete but if you are parking a car 150mm would be safer ( with a layer of mesh and saw cuts)

davkav

Ronney wrote: »

To stop water running through would you consider just putting an Aco Channel across the door threshold?

Is breaking out the existing not an option or considered too much work?

Yes you can get extender rings for AJ's and Gullies.

Footpaths would have a 100mm min concrete but if you are parking a car 150mm would be safer ( with a layer of mesh and saw cuts)

I think I will put a channel in either way, to stop water pooling.

I hadn't considered breaking out the existing tbh. Would there be any impact to the perimeter wall or foundations of the house? Or is the concrete generally poured after both have been built?

Ronney

davkav wrote: »

I think I will put a channel in either way, to stop water pooling.

I hadn't considered breaking out the existing tbh. Would there be any impact to the perimeter wall or foundations of the house? Or is the concrete generally poured after both have been built?

The concrete path beside the house should be a good bit above your foundations. It would have gone in after as there are pipes connect back into the house under it.

Section by the wall should be similar, I'd just check that the path isn't the foundation and the boundary wall built on top of it.

I'd suggest breaking out a small section as a trial beside each wall 300x300. that will give you an idea of the make up/dept.

GreeBo

Would you consider just building a threshold under the doors and see what that does for you?

Any water outside that area should be directed away from the house anyway, is there a specific source or its just general runoff?

mickdw

I wouldnt raise the levels there at all.
Id still regard that as an outside area and as such you must keep your ground level at least 150mm below floor level inside the house.

A nicely constructed 50mm or so threshold at doors with drainage channel outside that should keep the water out yet allow your car to get in without obstruction.

davkav

Ronney wrote: »

The concrete path beside the house should be a good bit above your foundations. It would have gone in after as there are pipes connect back into the house under it.

Section by the wall should be similar, I'd just check that the path isn't the foundation and the boundary wall built on top of it.

Good point, and now that you say it I remember there is a 1" gap between the boundary wall and concrete path.

GreeBo wrote: »

Would you consider just building a threshold under the doors and see what that does for you?

Any water outside that area should be directed away from the house anyway, is there a specific source or its just general runoff?

I think that may be the way to go. I'll put a drain in across the front of the garage door, and then add some draught blockers at the base of the door.

The rainwater is running more front to back of house through the garage rather than towards the house.

mickdw wrote: »

I wouldnt raise the levels there at all.
Id still regard that as an outside area and as such you must keep your ground level at least 150mm below floor level inside the house.

A nicely constructed 50mm or so threshold at doors with drainage channel outside that should keep the water out yet allow your car to get in without obstruction.

Another good point, and besides 150mm is bit of step up for the car even with a small ramp.

I think my options are as follows:
Investigate if it is worthwhile digging up the existing concrete and laying new.
Failing that I can dig in new drains across the front and back doors and just live with the two slabs of concrete being at slightly different levels.

Like I said I don't want to throw mad money at this if there is a possibility of us building an extension in the coming years.

GreeBo

davkav wrote: »

Like I said I don't want to throw mad money at this if there is a possibility of us building an extension in the coming years.

I'd start with something like this and see if anything else needed.
(The corresponding on the base of the doors should see you right imo!)
You can get 2.5M for €30 on screwfix and unless you have a serious water problem, 10mm should be loads?

Calahonda52

I poured a new floor in mine and used these
https://galco.ie/recessed-manhole-covers/
to make the Aj's 100% airtight and cable of taking heavy point loads
They have a grove for a soft car grease seal

Fine Cheers

I agree with suggestions to leave as is and go with improved threshold detail to gates.
Looks to be a fair cross fall at gate, have you somewhere at low spot to connect surface water to ?
Aco drainage channels are cheap enough (€15 per lin m) and would help also once you have somewhere to connect to.