How To Make / Mix & Use Mortar For Repointing Brickwork / Ridge Tiles
How to make mortar
Hello, this is a guide on how to mix sand and cement to make mortar. This is very useful for various DIY projects around the house, including roofing work like bedding or pointing of ridge tiles, replacing bricks and pointing stone or brickwork.
Although it is not particularly difficult to do, there are a couple of things to know. I've been making and using mortar for years so read on to find out how to do it right!
Sand and Cement
The simplest way to mix mortar is as follows. I use 1 part cement to 3 parts sand. Use builders sand. If you want the dry mortar to be dark, use red sand. If you want it to be light, use yellow sand. I mostly use red sand as it doesn't stand out so much as it is darker, so unless you have a specific reason to use yellow sand to match what you may already have on there, I'd recommend red.
If you're mixing by hand, then depending on how much you need you either need to use a bucket or a board.
If you only need a small amount of mortar then it can be alright to do it in a bucket. The easiest way is to put the sand and cement in with a trowel. You can count in 1 heaped trowel worth of cement, to 3 trowels worth of sand. Then repeat with more cement and then more sand as you fill the bucket. If you do it this way then it makes mixing it up easier as it's already pretty much mixed as you've put it in.
Don't fill the bucket more than just over halfway or it will make it too difficult to mix it all up correctly. Put the sand and cement in and mix it up thoroughly with your trowel before you put any water in. Once you put the water in it becomes more difficult to mix, it's a lot easier to do it dry.
Add this to stop cracking and make the mix smoother for pointing
Once you've mixed it all up thoroughly, then start to slowly add the water and also some plasticiser. The plasticiser is important as not only does it make the mortar easier to work, it stops it cracking when it dries.
Mix as you add the water slowly, until you get the right consistency. The easiest way to check the consistency is right, is to use the top of a clean trowel to lift the mortar from the bucket then hold the trowel on it's side. You want the mortar to stick to the trowel a bit, but not completely so it slides off slowly. This is about the right consistency. If it's too dry then it won't point properly and if it's too wet, then it will slide out.
You also need to check by smoothing it off in the bucket with the trowel. It should be a nice smooth finish with a small amount of foam bubbles visible. If you can see any cracking or a sandy texture, then add more cement. If it gets too sloppy, don't worry, just add a bit more sand. If you don't have enough cement then when it drys the mortar will crumble. If you stick to the 3 to 1 method, you should be fine, but now and again you'll need to add a touch more sand or cement. Ideally you should use the same proportion of sand and cement for all of the pointing you're doing, then it will all dry the same colour, but a trowel worth here or there of sand or cement more per bucket won't make a difference.
If you're mixing on a board, or in a wheelbarrow, the same thing applies on a larger scale. Mix dry, then add the water. If using a barrow, you can fit two bags of sand and 2/3rds of a bag of cement in there without overfilling. You still want to use the plasticiser and you will still need the trowel to check the consistency after you've mixed. If you're using barrow or board, then it's a good idea to put a tarpaulin down underneath, so any splashes are contained, rather than going all over the garden/driveway or wherever you're mixing.
If you're mixing in a cement mixer for a larger job, then the easiest way to add the water is to spray it in with a hose. Make sure that you add slowly and let the mixer do the hard work. If you put too much water in too quickly, it will start splashing out everywhere and it can fly quite a distance so be careful! It can be an idea to use goggles when you're mixing with a mixer as it is pretty painful if some does happen to splash into your eye. The important thing to remember with a mixer is to not let the mortar dry in there. After emptying it out, then put some water in there and some loose half bricks or pebbles, let it swill round then empty out. Then hose it out. If you do this while the mix has just been freshly made, it's a lot easier to clean out than if you let it dry..
This brick wall needs repointing. Don't go over the top of the old stuff, rake it out and do it properly!
Make sure when you start handling the mortar that you have gloves on. Cement can cause a reaction with your skin, it dries it out and cracks it and that can be painful. It doesn't take much to do that and if you're pointing for several hours without gloves, then you'll certainly feel it.
When you start pointing, depending on how and what you're pointing, then it can sometimes be beneficial to add the mortar in stages. If you have large gaps to fill, then put a layer of mortar in rough, then leave it to dry for a few hours. You can then go back and point it up with a bit more to finish. If it is a large gap, then if you try to do it all in one go, it can look great when you've first done it, but when you leave it, then it slowly slides out and leaves a gap at the top. You don't want this! If you're just doing brickwork or small gaps then you don't need to worry and can usually do it in one go.
If you're going to point properly, then you need to get as much of the old mortar out as possible using a grinder and then a handbrush, til there is no loose mortar left. If you just go on top of old stuff that's loose, then the new mortar you put in will just come out again, so if you're going to do it, then do it right.
If you're repointing or rebedding ridge tiles, then it's normally worth taking the old ones off and cleaning all the old mortar off, using either a brush, or sometimes a hammer and bolster (a mortar chisel) depending on how stiff the old mortar is. If you don't crack them, you can usually reuse ridge tiles. If you just go over the top of the old mortar, it's a lot quicker but what you put on will crack and fall off. What most roofers do is put the mortar line down, then use broken pieces of tile between the ridge tiles mixed in with the mortar to add some strength. This stops it from dropping down between the ridge tiles and allows you to build it up effectively.
Make sure that you keep your trowel clean. This will make the whole process easier. As you point, you will need to repeatedly clean the trowel off on the side of the bucket or something similar to keep it clean and clear and of course, when you're done then give it a good scrub, ready for next time.
Well this is a pretty straightforward guide to mixing up sand and cement into mortar and then pointing. Just make sure you don't forget to use plasticiser, add the water slowly and take your time when putting it in/on and you'll be fine.
I hope you found this article useful, if you have any comments, please leave them below. Thanks!
- Flat Roofers Nottingham Derby
Rain Defence Roofing cover the Nottingham & Derby area. Our roofers specialise in replacing old felt roofs with EPDM rubber flat roof membrane & installing uPVC fascia & guttering.
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