Raised Brick Beds in Garden?

Question

I am making a large raised bed from bricks for my mum in the garden so she doesn't have to bend so low to tend the garden.

It is two bricks thick, has piers for strength etc.

My question is, Do I have to put a DPC or even a DPM in the bed?

The earth will be touching the bricks obviously.....or should it? Do I put a membrane down the inside of the bed over the brick?

This website, http://www.pavingexpert.com/featur03.htm shows (if you scroll down) the use of one in a retaining wall.

Do I need it in my raised bed?

Please help!!

By the way the raised bed is an 18' by 5' rectangle!!

I have put in piers!!

Thanks everyone for your help on this.

It's a big raised bed, by the way, 5 feet wide by 18 feet long in the shape of a capital 'L'.

Answer 1

i would make it out of engineering bricks ..put piers in each corner and one in the middle each side ..don't want any dpc ore any other sort of membrane with engineering bricks or blue bricks the brick will not frost ..don't buy semi engineering bricks ..mortar 3 to 1 ..by weight not volume ..your mums gonna lo ve you !

Answer 2

Brick Raised Beds

Answer 3

Where are you located? This will make a difference on how deep your footing has to be.

Go back to the website you have linked in your question.

Look at the retaining wall - scroll down to the bottom.

This is similar to the your raised bed. You do not need the gravel all the way up the wall as shown in the diagram for the height of your wall. You also will not require the step as shown in the diagram.

Remember that the soil will be in contact with the wall almost to the top. The DPC/DPM will not do any good.

One thing you will have to do is place a layer of crushed stone in the bottom of the raised bed about 15 cm deep and run tile out to drain it.

Place a layer of lanscape material over the crushed stone before adding the topsoil. This will prevent the stone from being clogged up with silt.

Make sure the inside of the raised bed is smooth ( parging the inside wil accomplish this - you could also apply waterproofing tar over the parging). This will help prevent frost damage.

Also line the inside of the raised bed with at least 12 mm thick of styrofoam sheeting (white beadboard type). I recommend 25 to 50 mm thick. Make sure the tar if used is completely dry before lining with the styrofoam otherwise it will dissolve the styrofoam.

This will act as an expansion control. As the earth freezes and expands, the styrofoam will compress reducing pressure on the retaining walls of the raised bed.

Good Luck.

Answer 4

You don't say how high you intend to build the rectangle, a comfortable height would be around 2 to 3 ft. and if it's two bricks thick and the bricks are well laid, piers would not really have been necessary, but as you have already put them in it will certainly add strength, on the lower course you should leave a gap between bricks every 3 ft.or so, (called weep holes) to allow excess water to drain away.

You will not need any kind of damp course or membrane. As a membrane would trap the water and your plants would drown, yes they can!.... A retaining wall is designed to support a very large volume of soil, and is not the same as your project. no special bricks needed ! you're not building a house.

Up to now you have done very well, good luck.JL.

Answer 5

I wouldn`t bother with any sort of damp course. modern cement is waterproof so in reality dpcs` are not needed.
Victorian Lime/sand mortar was -and still is -porous, That`s why Dpcs` became a requirement. They don`t have them in most European countries.
The dirt will touch the bricks, that`s fine.
Quite possibly building regs require one for a retaining wall.

Answer 6

You only need to look at brick walls around gardens to see what happens when water gets to the bricks, they flake off.
For a really good job use a cement base, then a DPC, then line the trough with 400+ gauge polythene. Cap the wall with more engineering bricks or concrete blocks. It costs but ---- if you think you will not be there in two or three years just slap it together!
RoyS

Answer 7

Goodness gracious . you dont need a Damp proof course in a garden outside .Do you think the bricks will stay dry in the rain. You would be building in effetc a swimming pool and the plants would float away

Answer 8

Unless you have gaps in it like a half inch or better big, that the soil will wash out of, you don't need any liner for it. Just pack it in behind the brick like you would if you were planting something there and it should be fine.

Answer 9

there is no need for a dpc or dpm , all you need to do is keep the wall the same dimentions as it is now and build away lol .


i,m a bricklayer

Answer 10

extremely tough task. research at google or bing. that will can help!