Mortar/Cement to Use on Raised Brick Bed

[Stubbsk]

First post, hello everyone!

We have just bought our first flat and I'm currently making a few changes to the garden. Next to the raised bed with bamboo in it (see pic below), there was a raised bed with a bay plant in it that I have just removed to add a little extra space to the small lawn we have.

Another reason for removing the bay bed was that the paint was flaking and the mortar/cement coating was crumbling away. Basically, although both beds were made by the previous owner, he made the bamboo bed weatherproof and the bay bed not so much.

So my questions are then:

1. How come one raised bed become weather damaged whilst the other did not?
2. What mortar/cement should I use to coat the exposed portion of the remaining raised bed? Specifically weatherproof/outdoor material, method of mixing, etc.
3. What paint do you recommend to finish the job?

Thanks!

 

[r896neo]

You need to use a liquid dpm like synthapruf and then render over the top with two coats of render.

5 parts plastering sand to 1 part cement. Your first coat will need to be about 10mm thick and have waterproofer in it then your top float coat just 5:1.

Then paint it with masonary paint. Pliolite is better than water based for resisting moisture.

 

[Stubbsk]

Thanks

The previous mortar was very sandy, and I got the impression that was the issue.

Would this product do the job? http://www.diy.com/departments/u-can-waterproof-repair-mortar-5kg-tub/237084_BQ.prd

Or is this overkill for a raised bed, given that it's recommended for drains?

I was thinking of touching up other brickwork whilst I was at it, would it be a really bad idea to use this stuff on house brickwork around the drain area, and on a garden wall?

 

[r896neo]

Forget the premixed stuff it will not work as render. It will be fine for repointing brickwork etc but its a mix of probably 5 parts building sand to 1 cement and for plastering you need to use plastering sand.

Best off buying a bag of plastering sand and a bag of cement. You could happily use that for repointing too but you'll find building sand difficult to render with.

Youtube a video on rendering basics for some ideas.

My recomendation of two coats the first with waterproofer is the correct and long lasting way to do the job. Putting on one coat and painting it may last for 5 years or more but will never be a long term quaility job and may crack and blister your paint finish badly in the short term.

 

[Stubbsk]

Thanks, that sounds like a good plan. I'll get a good mix with the plastering sand and use for both.

Who only waterproofer in the first coat? Would the paint not adhere to the waterproofed cement?

What's the waterproof additive I need? Would these two from Wickes and B&Q do the trick?

Cheers

 

[r896neo]

Yes the one from bq is fine. You don't put waterproofer in the second 'float coat as you'll need to trowel and float it to get a good tight finish. This trowelling would keep drawing the waterproofer out and make it very hard to finish cleanly and smoothly