Mortar cracking around brickwork, advice needed

[iv211]

Hello,

We had all wooden windows replaced over the past 6 years (oldest to most recent). We obviously had some extreme weather recently and it is only this year that we have noticed some cracks around windows in our house. The house was built 1996 on clay soil and is a cavity wall with brick face construction.

The three south facing ground floor windows have different levels of cracking horizontal and on the edges above the window (two layers - one vertical, one horizontal above lintel tray. There are a few hairline cracks below the window. There is nothing visible happening on the south side inside the house. The south window towards west has most cracks (see pictures). This is the most recent window installed two years ago. The patio door next to it has slight cracking in the same area, and that was installed more than 15 years ago. I have a feeling those cracks have been there the whole time.

North side it's the opposite corner of the house where there are some cracks above and below the window. There is a big tree in vicinity, although that has now been considerably cut down. Most rooms have a vertical weakness under the window sill where the plaster boards meet, and this year we noticed under this window and in the room above it the crack a bit more - it was about 1mm as opposed to hairline.

My question is: are these normal thermal expansion cracks or is there anything that we need to worry about/fix urgently? We are in East Anglia and see comparatively little rain.

Many thanks in advance for your advice.

 

[motorbiking]

The cracks in the walls are pretty minor, the cracks around the windows a bit more interesting. it could be the lintel has been disturbed by the replacement windows.

 

[Justin Passing]

Clay does heave, check your neighbours.

 

[iv211]

The cracks in the walls are pretty minor, the cracks around the windows a bit more interesting. it could be the lintel has been disturbed by the replacement windows.

Thanks for that. If the lintel was disturbed, what would be the next sensible course of action? We are not planning to move for a few years, so my thinking here is to prevent it from getting worse, rather than potential survey implications.

 

[iv211]

Clay does heave, check your neighbours.

Yes, I am aware, but I read that most of English estates are built on clay. No obvious signs of subsidence amongst the neighbours as far as I can tell.

 

[iv211]

The cracks in the walls are pretty minor, the cracks around the windows a bit more interesting. it could be the lintel has been disturbed by the replacement windows.

Just checked, and pictures from 3.5 years ago, with old windows in situ, show the same horizontal crack along the top.

 

[motorbiking]

And no movement since?

Could just be lintels were not packed properly when installed and have moved slightly - as in bedded in.

 

[iv211]

And no movement since?

Could just be lintels where not packed properly when installed and have moved slightly - as in bedded in.

Seemingly not according to my photos....

 

[motorbiking]

Then the solution would appear..
chip out the loose stuff and repair with a small bag of mortar. Ideally you don't want wasps etc finding a nice home in your wall cavity, via the holes in the mortar. Also water can get in and freeze in the winter, causing expansion damage.

 

[iv211]

Then the solution would appear..
chip out the loose stuff and repair with a small bag of mortar. Ideally you don't want wasps etc finding a nice home in your wall cavity, via the holes in the mortar. Also water can get in and freeze in the winter, causing expansion damage.

Thanks, that sounds like a good course of action. Can you advise how to bets get a match on existing mortar?

 

[Pat ex]

Thanks, that sounds like a good course of action. Can you advise how to bets get a match on existing mortar?

There's the problem.
Colour tends to be relative. It will vary a bit according to the surrounding material.

 

[motorbiking]

I think you will be lucky - the colour isn't too yellow - standard readimix mortar will be pretty close. if not you can get mortar pigment for a few quid.
Do a little bit and see how it looks. The other option is to bodge it with clear silicone.

 

[Notch7]

the windows have nothing to do with the cracks -its a modern house with catnic style lintels.

the crack above the soldier course is slightly odd as that is the top of the lintel line.

mortar matching is tricky as the colour is determined by the colour of the sand -contractors pretty much always use local merchants -and what you find with local merchants is they will use sand from local quarries, usually theres only a choice of 2 or 3 different sands.

You might be best to go to a builders merchant and ask what their sand is


If you buy a 25kg plastic bag of sand that may not be local quarry and is less likely to match

 

[iv211]

the windows have nothing to do with the cracks -its a modern house with catnic style lintels.

the crack above the soldier course is slightly odd as that is the top of the lintel line.

mortar matching is tricky as the colour is determined by the colour of the sand -contractors pretty much always use local merchants -and what you find with local merchants is they will use sand from local quarries, usually theres only a choice of 2 or 3 different sands.

You might be best to go to a builders merchant and ask what their sand is


If you buy a 25kg plastic bag of sand that may not be local quarry and is less likely to match

Thanks, this is really good advice.

 

[^woody^]

The horizontal crack above the frame is movement of the panel on the cavity tray, and is common. Cracked when built or anytime after. There is a lintel there.

The other cracks are insignificant.

I've not read the text, so just assumed what the question was.