How to Cut a Concrete Block

so this is a quick video showing you how to cut a concrete block this is a 7.2 newton concrete block which is a fairly standard offering in the uk and can be used for a number of different purposes laid vertically or on its side so to cut it i'm using a a brick bolster which is around four inches i've got a bolster hammer which is a two pound one and um a bricklayer's trowel which we can use for cleaning up the cut after we've made it so the blocks will be cut lengthways and that's because they're going over lintels around the top of the final course of blocks on this particular project so you put them in a heap that gives you a nice sturdy base to cut the block on um and uh and also a bit higher to help your back it's important to check in between the two blocks to make sure there are no little bits of gravel or fragments of block which can cause point loading when you're trying to cut the block with the hammer and bolster because it will cause the block to break so get the block underneath the block you're cutting a good scrape with a a trowel to clean off any little bits left over so first off is to measure your cut so you want to leave about 10 millimeters for mortar maybe a bit more and then i normally subtract about five millimeters from the height you want to allow for any irregularities it's better to have the block a little bit smaller and make up the difference with mortar um so we use the bolster there to score a mark on the top of the the block uh where we want to make the cut and then we're ready to go so we pick up our bolster hammer and we start to gently chisel a groove along the top of the block and you can see the groove doesn't have to be overly straight but uh the straighter is the neater really and so do try and keep it straight but it doesn't have to be perfect so we just go along gently tapping each time i'm probably taking a bit more time than i normally would here you could go a bit faster if you want but if you if you try and rush it and hit the bolster too hard then it won't um it will probably break in an irregular fashion and you'll end up with a very awkward probably angled cut with lots of jagged bits and it won't be any good so you can see there i'm being careful not to get any of the bits on the block below so to avoid that point loading i was talking about give it a clean off there with a hand or a trowel and then you can't see it i'm afraid because it's off the top but i'm just scoring the top of the block with the bolster as we did at the start just to mark where the cut is and carry it across you can see the very faint line on the end and then we continue the line our chiseled groove on the other side all the way along and we're still being quite gentle at this point we just want to make a nice sort of um consistent groove as straight as possible along the cut line now when we when we've made the cut line quite well then we start to hit the block a bit harder then in order to try and cause it to fracture now you can see that started to go but rather than just hit the block where it's begun to crack keep moving the bolster along and hit it in some other places because if you just keep hammering in the same spot there's a risk of that piece that you're trying to get off breaking into and it might be more useful to you to keep it whole such as is there so after we've done that you can see we've got some slightly high points on the block and we'll just use the edge of the trowel a bit like an axe to trim those off and it's quite important to do that because if you have little bits poking out then when you lay the block they might poke down through the mortar and cause the block to sit on a strange angle um but uh most of those have been trimmed off now so that's um that's good so now just to show you how to cut one uh vertically we'll just do one quickly here so this is kind of a full speed one here make a line across one side um score across the side and then continue your line across and when you make the line all the way across give it a damn good whack in the middle and um and it should break cleanly like it has the trim it up with a trowel and you're ready to go so uh that's about it really uh so excuse for a slight mismatch between the voice over and the uh and the camera but the original sound quality was quite bad so i thought i'd re-record it for you guys okay thanks very much cheerio bye

Channel: Dorky Thorpy

Views: 10,358

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Id: uLy7gC-g8T0

Length: 5min 45sec (345 seconds)

Published: Wed Oct 07 2020