John543219 Posted July 9, 2023 Share Posted July 9, 2023 New double floor extension, just had windows fitted and noticed crack from the top window on the first floor vertically down to bifold below after they went in and were installed. Very good deep foundations with the build at 2.5m so don’t think movement or subsidence (hopefully not)… Should we be concerned??? The exterior is about to be rendered so want to ensure all ok before this is done Any advice appreciated so we can get a good feel for what this might be 👍 Link to comment Share on other sites More sharing options...
Dave Jones Posted July 9, 2023 Share Posted July 9, 2023 what type of lintel was installed above the bifold ? Link to comment Share on other sites More sharing options...
John543219 Posted July 9, 2023 Author Share Posted July 9, 2023 Steel RSJ Link to comment Share on other sites More sharing options...
Iceverge Posted July 9, 2023 Share Posted July 9, 2023 I wouldn't worry about that. How long since it has been built? Link to comment Share on other sites More sharing options...
John543219 Posted July 9, 2023 Author Share Posted July 9, 2023 (edited) About 2 weeks since appeared, extension has been up couple of months Edited July 9, 2023 by John543219 Link to comment Share on other sites More sharing options...
Dave Jones Posted July 9, 2023 Share Posted July 9, 2023 wouldnt worry if its an RSJ on a padstone. That blockwork is rough as feck mind. Link to comment Share on other sites More sharing options...
Iceverge Posted July 9, 2023 Share Posted July 9, 2023 Put a couple of these on it, take regular pics of it and save it to the cloud. Delay rendering until all movement has stopped. Link to comment Share on other sites More sharing options...
John543219 Posted July 9, 2023 Author Share Posted July 9, 2023 Thanks for this, great advice and will get a few of these on it next week 👍 Link to comment Share on other sites More sharing options...
George Posted July 10, 2023 Share Posted July 10, 2023 (edited) This is most likely due to the concrete blocks shrinking slightly. This happens post manufacture and continues for some months, conditions depending. It can be dealt with by putting in movement joints when blockwork walls are 6m+ (although unusual in domestic settings), but cracks can happen in other circumstances. The line of the wall with a window is a relative weak point so has cracked along that line. Now the crack has occurred, ongoing movement should be minimal. But monitoring will help confirm that. The cracks should be ground out and repointed. If the crack has gone right through I would consider adding in stainless steel helical bars to crack stitch (aka helifix bars) Edited July 10, 2023 by George Link to comment Share on other sites More sharing options...
John543219 Posted July 10, 2023 Author Share Posted July 10, 2023 Thanks for this George, appreciate advice and makes sense Think expansion / contraction of RSJ with heat etc has also come up on a few searches and info will look at sorting with helifix bars 👍 Link to comment Share on other sites More sharing options...
Gus Potter Posted July 13, 2023 Share Posted July 13, 2023 What is on the inside? another masonry leaf? If so does the crack appear on the inside. If so you may have a problem on your hands as the tying together of the building needs to be checked. How long is the wall? On the other hand it could just be the blocks shrinking and the crack manifests at the weak spot. 1 Link to comment Share on other sites More sharing options...
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