Vertical cracks on external brick wall

[johnss77]

Hi!

I'm looking at making an offer on a house, but I've noticed that it has some cracks on an external brick wall. They seem narrow and not extremely long, but a few bricks are cracked. This is at a corner of the house. It is impossible to see if there are cracks inside, because it's a kitchen with fitted cupboards. The house is quite new, just 8 years old.

I'm not sure if I should pay for a structural survey, so I would appreciate any feedback. Here are some photos attached.

The biggest cracks are on a South-facing wall near a corner. There is one at the bottom of the wall (about 3 feet long):

Crack South-facing 1

• johnss77
• 18 Apr 2013
• 1

Crack on South-facing wall, near corner (bottom)

There is another one 4 feet up (about 3 feet long, too):

Crack South-facing 2

• johnss77
• 18 Apr 2013
• 1

Crack on South-facing wall, near corner (top)

The cracks don't seem to extend to the foundations, but the patio at the base of the corner seems to have slightly dropped:

Base of the corner

• johnss77
• 18 Apr 2013
• 1

Base of the corner, patio slightly dropped

The East-facing wall has another crack near the same corner:

Crack East-facing 1

• johnss77
• 18 Apr 2013
• 1

Crack on East-facing wall, near corner

The East-facing wall also has a crack below a window:

Crack East-facing 2

• johnss77
• 18 Apr 2013
• 1

Crack on East-facing wall, below window

And that's it. Also, there is an extension attached to the East-facing wall (at about 6.5 feet from the corner mentioned). Could it be related to the extension?

So, what do you guys think? Do you think this could be a serious problem? I read online that it can be due to thermal expansion, but I am not sure if this is the case. If it is not worrying, I would prefer not to pay for the structural survey. Especially, because the house is a detached house and all the other external brick walls seem to be fine.

Many thanks in advance,
John

 

[Tipper]

Time for a structural engineer methinks!

Are you unsured?

 

[tony1851]

I read online that it can be due to thermal expansion, but I am not sure if this is the case.

It's unlikely to be thermal expansion as the coefficient of thermal expansion of brickwork is very small

If the cracks don't extend below the dpc it's unlikely to be settlement either.

Hard to tell without seeing the whole context, but could possibly be either;
initial shrinkage of an over-strong mortar leading to stressing and cracking of the brickwork; or, the initial expansion of the bricks themselves (this usually manifests itself at the corners of relatively long walls).

If it's any of these, the cracking has probably stopped by now and should be nothing to bother about.

 

[^woody^]

It's classic shrinkage at a common places in the panel.

AKA thermal movement

The bricks are dry and the mortar too strong. Is not serious, it tends to be a once only event. Filling with clear silicone may be the most appropriate repair

 

[tony1851]

It's classic shrinkage at a common places in the panel.

AKA thermal movement

Are you saying it's shrinkage, or thermal expansion?

 

[^woody^]

It's shrinkage. The technical term is thermal movement.

No cracking can be due to expansion

 

[tony1851]

It's shrinkage. The technical term is thermal movement.

No cracking can be due to expansion

I have to take issue with you there, Woody. Bricks undergo an initial (and irreversible) expansion; being kiln-dry at first, they gradually take up atmospheric moisture and thereby expand slightly.
Thermal movement (expansion in heat and contraction when it cools) is reversible and is independent of the initial expansion of the brickwork.
This is basic stuff, surely.

 

[^woody^]

When laid in a wall, how can a gap (ie crack) be caused by expansion?

If you are saying that shrinkage cracking is not thermal cracking, then you need to see about getting all the text books changed and the industry reeducated

 

[tony1851]

When laid in a wall, how can a gap (ie crack) be caused by expansion?

If you are saying that shrinkage cracking is not thermal cracking, then you need to see about getting all the text books changed and the industry reeducated

I don't believe I've just read that.

 

[joe-90]

Ding Ding, seconds out - round three.

 

[stuart45]

Brickwork expands in the heat of the day and when it cools at night it shrinks and cracks. It normally cracks on the long runs of brickwork in the weak spots above the frames, or at the quoins where the other wall holds the quoin brick in place, so I suppose woody is correct in that it cracks in the shrinkage cycle.

 

[tony1851]

Yes, brickwork expands and contracts with heat and cold - that's to be expected. But in this country, thermal movement over the variation in temperature which can be expected is only about 10% of the long-term irreversible expansion of the brickwork.

 

[stuart45]

It still actually cracks as it shrinks. That's why it's cracking in the corner, as it pulls away from from the quoin. You could argue that expansion has had a part in the problem.

 

[tony1851]

This is an east-facing wall with pilasters at about 13ft centres and no expansion joint. Crack caused by long-term irreversible expansion of brickwork, independent of the day-to-day variations caused by temperature changes.

Untitled

• tony1851
• 18 Apr 2013
• 1

Untitled

• tony1851
• 18 Apr 2013
• 1

 

[stuart45]

https://environment7.uwe.ac.uk/resources/constructionsample/Conweb/defects/cracking/print.htm

Scroll down this article fron UWE. It explains about shrinkage cracking in brickwork.
BRE have also done plenty of research into it.
The picture you put up does not really prove what caused the crack.