Building red brick step on top of tarmac

Hi, a small red brick step won't effect the tarmac provided it is a well compacted layer. If it's only one brick high a foundation is not required.

Hello, by all means you can lay a course of bricks on top of tarmac in order to form your step. However, tarmac is a very soft aggregate, especially when warm. It is designed that way so that it can almost be self repairing (to a certain extent). For example, if there is movement in the ground on which the tarmac has been laid, the tar (the material used to bind the aggregate) will mould into the new shape in order to keep it held together, unlike concrete which uses cement as the binding agent, which completely hardens and will not move but crack under severe movement (many years of natural ground movement). Now it will depend completely on which aggregate the tarmac has been laid onto, as to how long your step will last. If it is has been laid on a concrete base then yes, very suitable. However, if its been laid on a aggregate without the use of cement such a scalpings then sooner rather than later you must be preapred for it to move a therefore leaving cracks in your brickwork. If you are prepared to, in time, re-lay your bricks forming your step then go ahead and safe yourself the effort of digging out a small foundation. I would recommend a strip foundation of no more than 150mm wide by 150mm deep. This would be ample for a couple of courses of bricks to form your step. It would not cost you much for a few small bags of ballast on top of your already bought cement. And you will have the peace of mind knowing that your step is going to be a lot more durable, therefore lasting a lot longer than if you were to lay straight onto the tarmac. failing this the least i would to would be to break up a small amount of tarmac (in an area in which you will cover with your step) to check whether or not the tarmac has been laid on a concrete base. Enjoy building your step!

I would cut out where the brickwork is going and lay concrete down before laying the bricks . You know it’s a solid base and it would be easier to get your level right.

The base laid for the tarmac driveway, will have been designed to carry vehicles, so pedestrian traffic shouldn't pose any problems. Advising to cut through the tarmac and remove the base layer to a depth of 100mm x 150mm wide, forming a strip around the edge, fill with concrete to just below the surface of the drive then lay your bricks! This will be suitable for the 1 or 2 courses of bricks you intend.

You can not build a step that will itself be heavy, and potentially have people standing on it regular. It deffanately needs to have a small foundation of concrete back down to solid ground. Tarmac does and will soften in hot sunshine and move / loose it's strength. This will allow the brickwork to move/ sink/ not stable. 100% small foundation back to solid ground. Jim