Building a raised bed against brickwork.

[TomB]

Hi
We have a patio that extends out from our house to the garden. The patio has a small down to the garden but alongside the step there is a wall which has a 50cm drop from patio to the lawn. Its a tiny drop, not dangerous.
The edge of the patio that overhangs the drop is pretty dangerous - we have toddlers who are forever climbing up and hurting themselves on it and our fear is they run, trip and hit the hard patio edge.

We want to install a border / very small raised bed to act as a barrier between the patio and lawn. We are planning on using railway sleepers to act as the border. We wondered if we would need to put a barrier between the soil and the small brick wall that makes the front of the patio? The brickwork isn't connected to the house at all (its about 4 metres away from the house), but we wondered if damp soil against brick work could cause any damage.

Thanks!

 

[sugarapsa]

Short answer is yes, moisture is the worst for masonry including foundations. There are several "Silane/Siloxane sealers" that can be used in conjunction with mesh. However, you may want to research this further as these type chemicals are not what you want if produce will be planted in the raised bed.

 

[DirtMechanic]

I suggest a small space large enough to access for termite and other maintenance needs.

 

[Tetters]

We don't have termites in the UK !! If the wall is not connected to the house, I wouldn't worry about it being wet, and I wouldn't use any chemicals on it either. As for the sleepers, it might have been a concern if they were the very old original tar filled ones IF you were growing vegetables there, but not if it's just a flower border. I have a similar raised area for ornamentals, and those tarry sleepers, and over the years they are still solid with no ill effects on the plants. If the sleepers are the newer cut ones though, it could be an idea to put a plastic barrier between them and the soil. It would be nice to see a photo of the finished job - please
Welcome to the forums Tom

 

[Oliver Buckle]

Hi, I have a similar patio and wall and have thought about doing something as it is a pain to mow up to. I was considering a very low hedge along the edge, maybe box. No sleepers etc. required, it would cover the edge, would be easier to maintain than a flower bed, and adults could step over it if they wanted access to the lawn.

 

[DirtMechanic]

I would use something akin to a wicking board, polymer backed fiberglass, anything at all to prevent increasing the facial moisture intake of brick. Its not the best insulator to begin with and the mortars are designed to spread moisture with their lime heritage. Even with the air gap usually found between the brick facade and the wall no one designs that brick face for the permanent wet. They use other designs, just below the brick facade as it approaches the soil horizon. Spray liquid rubber foundation seal at a minimum.

 

[Oliver Buckle]

I don't get why everyone is so concerned about a bit of damp on the brickwork. It s not structural, it will simply be a couple of courses holding back the rubble under the patio, and most brick houses have two or three courses below the damp proof course that are permanently damp on the North side. If there is any sort of flower bed against the house the bricks below the DPC are in just the same position, except that the patio will be making a ledge above this brickwork, so It will be drier than normal. All this creating a gap and spraying with rubber strikes me like wearing belt and braces with a swimsuit.

 

[DirtMechanic]

I don't get why everyone is so concerned about a bit of damp on the brickwork. It s not structural, it will simply be a couple of courses holding back the rubble under the patio, and most brick houses have two or three courses below the damp proof course that are permanently damp on the North side. If there is any sort of flower bed against the house the bricks below the DPC are in just the same position, except that the patio will be making a ledge above this brickwork, so It will be drier than normal. All this creating a gap and spraying with rubber strikes me like wearing belt and braces with a swimsuit.

There is a lot going on at the base of any wall. Much less wall hollows with moisture. The moisture allows life. Molds to be sure but in my case scorpions are around and I hate those things. Then there is the direction of water pressures and so forth as one effectively raises the finished grade.

 

[sugarapsa]

There is a lot going on at the base of any wall. Much less wall hollows with moisture. The moisture allows life. Molds to be sure but in my case scorpions are around and I hate those things. Then there is the direction of water pressures and so forth as one effectively raises the finished grade.View attachment 102461

Perhaps a bit of an over kill although speaking as a retired General Contractor;
This will also serve to keep your huge tomato plants from knocking it over;