crowe Posted March 7 Share Posted March 7 Hi. After comments and thoughts please. I have a double storey extension built 15 years ago with a single storey adjoining utility room. The utility room was stepped back about 1.5 bricks from main extension. A crack has appeared, in the main extension straight up and down. started off as hairline now grown to about 0cm or more. Widest part is around the roofline join of extension. It does not continue to the ground. It has started to go upwards from here recently. Gutting comes down from the main roof on the same line.Does not extend inside through internal blocks. Anybody seen this before or have thoughts on causes?? Link to comment Share on other sites More sharing options...
markc Posted March 7 Share Posted March 7 Pics? If crack is wider at the top then it’s breaking its back … outer end is sinking or middle is heaving. Get some pics up and let’s have a look 1 Link to comment Share on other sites More sharing options...
joe90 Posted March 7 Share Posted March 7 Sounds like differential settlement but pics please. 1 Link to comment Share on other sites More sharing options...
crowe Posted March 7 Author Share Posted March 7 (edited) Edited March 7 by crowe Link to comment Share on other sites More sharing options...
markc Posted March 7 Share Posted March 7 That’s odd, do you have a pic from the front as well? Trying to work out how it’s bonded, appears the corners are a sort of wrap around brick? Link to comment Share on other sites More sharing options...
crowe Posted March 7 Author Share Posted March 7 Link to comment Share on other sites More sharing options...
markc Posted March 7 Share Posted March 7 @crowe thanks for that, must have been an optical illusion, so yes standards bricks and bond. Now for what is pushing the outer leaf away - could be the extension pulling but the crack is too focused and uniform. I did see something similar where the cavity was filled with a wool type insulation and it got wet, this corroded the ties and also added load pushing the outer leaf away. i strongly suggest you get a Structural Engineer or very good (not mortgage adviser) type surveyor to have a look. At the very least wall tie replacement but probably cavity clean out as well. 1 Link to comment Share on other sites More sharing options...
crowe Posted March 7 Author Share Posted March 7 29 minutes ago, markc said: @crowe thanks for that, must have been an optical illusion, so yes standards bricks and bond. Now for what is pushing the outer leaf away - could be the extension pulling but the crack is too focused and uniform. I did see something similar where the cavity was filled with a wool type insulation and it got wet, this corroded the ties and also added load pushing the outer leaf away. i strongly suggest you get a Structural Engineer or very good (not mortgage adviser) type surveyor to have a look. At the very least wall tie replacement but probably cavity clean out as well. Link to comment Share on other sites More sharing options...
crowe Posted March 7 Author Share Posted March 7 Thanks very much, I must admit I had similar thoughts re extension ( utility single storey) but the ties and corrosion etc would make perfect sense as the water from the main build roof doesn't half flow down gutter and always overtops where it joins extension guttering so it wouldn't take much to get in the crack etc and with expansion etc in winter you make alot of sense. Will get a structural survey to confirm but thankyou. Link to comment Share on other sites More sharing options...
George Posted March 7 Share Posted March 7 I think the extension walls are restraining the outer leaf, with thermal expansion and contraction in the original adjacent length causing a moment couple at the corner. This has cracked the brick vertically. This is a bit like in diagram 4 https://www.nhbc.co.uk/binaries/content/assets/nhbc/tech-zone/nhbc-standards/tech-guidance/6.1/movement-joints-in-masonry-walls-.pdf Wall tie corrosion tends to exhibit horizontal cracking, as the corrosion products jack the bed joints apart. 2 Link to comment Share on other sites More sharing options...
markc Posted March 7 Share Posted March 7 @George good point, I never considered a shear load at the corner, this would explain why the joint hasn’t opened / bowed the outer leaf 1 Link to comment Share on other sites More sharing options...
Hughgo12 Posted March 7 Share Posted March 7 Worth getting a structural engineer to look at. Without seeing the rest of the house and surrounding site it looks like thermal movement. Often seen on return walls, long panels and at corners. The extension probably has contributed to this as it will have thermal movement which differs from the house brick. I would monitor in the short term. It is unlikely to get worse. 1 Link to comment Share on other sites More sharing options...
crowe Posted March 8 Author Share Posted March 8 Thankyou George and Hugogo and Mark you all make a lot of sense. As you say it's not bowing the outer house wall and it's cracked down cement and through single bricks from the utility extension roof join where the lead is inserted into brickwork of main house. As you say the utility room extension will have differing thermal properties to the main house so this is likely to add to to it. I guess maybe need to look at some thermal joins. Link to comment Share on other sites More sharing options...
saveasteading Posted March 8 Share Posted March 8 Am I imagining the tiniest bit of level difference at the cracked bricks? I'd suggest that there has been a miniscule differential movement between two constructions, creating a stress. That line goes through the weakest line ( mortar to half brick). How wide is the crack? 2mm perhaps? Does a pound coin fit in? Worry. Not? Take a note of the gap, tell us so that it is on the record, and look again in 3 months. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now