Why Has My Screed Cracked? Don't just try to repair it, you need to investigate why it happened! скачать в хорошем качестве

Why Has My Screed Cracked? Don't just try to repair it, you need to investigate why it happened!

We are here to help. www.speed-screed.com - 0800 242 5589 - info@speed-screed.com Why Has My Screed Cracked? Should I Worry? I’m Andy Parkin, Managing Director of the Multi Award Winning Speed Screed. I’m here to answer the question, “Why has my screed cracked?” It is quite a difficult question to answer, however I will give you an overview and hopefully may give you some ideas as to why this may have happened. As with any screed issues, we need to look at the full picture. There is no point in just repairing the symptom, we need to deal with the cause first. If we only treat the symptom then we are likely to have the same problem again. To examine why has my screed has cracked, it should be noted that it is common to see cracking, and does not generally mean that the screeds integrity is affected. Shrinkage Cracking Screed shrinks, and there could be an elemental of shrinkage cracking. Control of the shrinkage cracking, is whereabouts it cracks. Is it okay to crack there, is it okay to crack there? Anything with water in will shrink as it dries, and unless there are controls in the screed, it will crack by itself to release the stress. Screed Breakdown When you experience cracking, it could be related to a general breaking down of the screed. You may start with a crack, but that might be a symptom of something else that is underlying and the screen may break down further. You may have an innocent crack that is then trafficked, loaded, then starts to break down, which is a different issue in itself. Substrate The screed will only be as good as the substrate that it is laid on. If the substrate is not sound, dry, contaminated, stable, insulation is rocking or you have gapping, there will be issues with the screed. Preparation is always key when working with screed. Has there been too much water, too little water? Too much water means that you are going to get excessive shrinkage and more cracking. If there’s too little water, then that means that the cement can’t hydrate or won’t hydrate all the cement particles so you are going to end up with a weaker screed. So, that may be an issue. Staying on the subject of water, has the screed been cured? So, when we’re saying cured, it means retaining for seven days the water within the screed. So, it’s not dried out too quickly, there’s not been wind tunnels in the building, certainly kind of may through to October time is key times when screed should always be cured, as per the British standard. So, the screed may dry out, you may end up with dusty surfaces. In extreme cases, you may experience some cracking because of weakness. It could be poor mixing practise on site. Now, that could be a multitude of things. It could be the way the screed has been mixed. Has it been mixed with just a shovel on a board? Has it been mixed in a free fall mixer so it’s not mixing properly? You’re ending up, you’re getting balling. Free fall mixer’s not suitable for a semi dry mix. Is it that there’s not enough cement in the mix? Has the cement ratio not been adhered to? So, that could be a reason why the screed starts to break down. Is it the wrong grade and quality of the sand? Is that suitable? Does it meet the British standard? Is it starting to break down because it is the wrong grade? Is it too fine? It may look a nice smooth surface finish, but if there’s no sand at the top end of the grading, it’s going to lack some strength. So, maybe it’s the wrong grading of sand. Compaction is a major consideration for sand and cement. So, it needs to be compact in layers. So, layers of 50 mm. So, if you’ve got 100 mm screed, that’s two layers. If you’ve got 150 mm screed, that’s three layers you need to be compacting in. If you don’t compact in those layers, then you’re gonna end up with a nice, crusty surface but then nothing substantial underneath. It’s gonna crumble and you may see a breakdown of the screed and also some cracking. Has the screed been trafficked too early? This is something that tends to happen on sites, busy sites. Contractors can’t wait before the next trades are getting in, so it’s early trafficking. So, that’s foot traffic, point loading, heavy loads are subjected to the screed. So, that can be, it can be impact as well so that you can see cracking related. So, all these things. The screed from the moment it’s laid to the time when the floor covering go on, British standard states that the screed should be protected at all times. Stress Relief Joints #screed #speedscreed #floorscreeding