New garage base

[Tricky Dicky]

I have a concrete sectional garage stood on what appears to be originally o n a concrete drive. The base itself is not flat and slopes in two direction s, the result being that the garage has a distinct lean with the concrete p anels being about 75mm out of vertical over their height leaving the flat r oof with the slightest of falls.

I want to replace the garage with a larger version probably a sectional ty pe again although at this point I have not decided on the material. To corr ect the slope of the base could I lay another base over the top of the orig inal? The new base even though for a longer and wider garage would be entir ely on the old concrete of the drive and base (the base protrudes beyond th e garage to the side to provide a hard standing area).

The base and garage we think have been there from the late 70's when the ho use was built and the drive and base looks in fairly sound condition with j ust one long crack running at an angle in front of the door, this looks lik e it's been there a long time and there is no movement in any axis. The new base would span the crack and would have a ramp from what is left of the d rive and hard standing area to the entrance and I am planning on using stee l mesh reinforcement within the 100mm depth.

Any advice would be appreciated, except the dreaded rip it up and start aga in! Incidentally we have just moved into the property and despite having ou r own survey done and going over it carefully we did not spot the problem u ntil we moved in. I just did not give the garage much of an inspection beca use it was always going to be replaced, there is a lesson there!

Richard

[Adrian]

Have a look at Warwick Buildings pre-fab wooden ones. Their pricing's decent, so we stopped in at their place a while back to have a look at the quality - very, very decent.

[Rick Hughes]

Ideally no ... but if you can put at least 100mmm concrete on top you should be OK .... and less likely to crack. Where there is a crack cover with a piece of reinforcing mesh, at least

750mm past the crack all round if possible. Or even put reinforcing mesh over whole of base .... 50mm from edge and set it mid point if you are putting in 100 concrete ... needs at least 50mm cover. I'd make a 20N mix to get strength in.

[Tricky Dicky]

Adrian, I have been considering a wooden garage but have been looking at ty pes based on log cabin construction. Part of the garage will be partitioned off for an office/workroom. I will have a look at the Warwick Buildings yo u suggested, thanks.

Rick, could you elaborate on what you would consider ideal, which I suspect means taking up the concrete for the area proposed for the new base?. My o ther thoughts have been to remove portions of the existing base and creatin g deeper strip foundations under the new garage walls. These strip foundati ons would rise above existing base allowing a top layer of concrete to form the new garage floor. A further question is due to the office/ workroom ar rangement will it be feasible to include moisture barrier with either of my proposals? Thanks for your response.

Richard

[harryagain]

I want to replace the garage with a larger version probably a sectional type again although at this point I have not decided on the material. To correct the slope of the base could I lay another base over the top of the original? The new base even though for a longer and wider garage would be entirely on the old concrete of the drive and base (the base protrudes beyond the garage to the side to provide a hard standing area).

The base and garage we think have been there from the late 70's when the house was built and the drive and base looks in fairly sound condition with just one long crack running at an angle in front of the door, this looks like it's been there a long time and there is no movement in any axis. The new base would span the crack and would have a ramp from what is left of the drive and hard standing area to the entrance and I am planning on using steel mesh reinforcement within the 100mm depth.

Any advice would be appreciated, except the dreaded rip it up and start again! Incidentally we have just moved into the property and despite having our own survey done and going over it carefully we did not spot the problem until we moved in. I just did not give the garage much of an inspection because it was always going to be replaced, there is a lesson there!

Richard

There will be a recommended base in the destructions. If you don't do a proper job the (usually ten year) guarantee will be invalidated. If it has a crack it is naff. You might put a base with some mesh on top of the original. The base is sized for the moving point load of the car, the garage is bugger all.

[Roger Mills]

Putting new concrete on top of old is seldom satisfactory. It's not that difficult to break up old concrete with the right tools. I had my caravan stand removed and turned into garden last year, when I gave up caravanning. The contractor who did it used a big spike on a JCB - in place of the bucket - and operated hydraulically rather than pneumatically. It was very quick and quiet - and the whole thing broke up into large but manageable chunks with very little drama. They broke it up and took it away on a lorry, all within a couple of hours.

If you start again, you can control the whole process, and lay good concrete which won't crack, you can control the level so that it won't be higher than desirable, and you can lay slabs of insulation under it - particularly the part destined to be an office.