Plaster Cracks vs Structural Cracks?

[Redacted]

Hi there,

I was asked to look at a few cracks in a building that apparently got worse after heavy winds recently.

I'll most likely need to give comment on the most likely cause of the crack and potentially a recommendation for a fix.

My thoughts are outlined below but I would appreciate the opinions/thoughts from you all.

For the image above, the cracks are mainly vertical and appear to be between 2mm and 5mm in width( I'll confirm this from a site visit) . Based on the age of the building, I'm assuming that the walls are built with limestone (common in my area for old properties)or hollow CMU block.

I believe the main cause for a vertical crack like this would be settlement of the foundation. Or it may just be a plaster crack. I'm leaning toward having them hack the plaster off the wall in this area, which would allow me to determine if the crack has gone through to the main structural wall. Is this a reasonable request that I can ask from the client?

If the cause is due to settlement and there are no signs of damage to the surrounding structural elements, I'd be inclined to just have the client hack and plaster the cracks for aesthetic purposes?

Any advice would be appreciated.

 

[msquared48]

Looks to.me that the corner column shifted laterally at a 45 degree angle at the floor. The molding opened up at the intersection too. Need to open up the base of the corner column and verify, perhaps adding corner strap after repositioning the column.

Mike McCann, PE, SE (WA)

 

[KootK]

By all means, open it up and get a better look. There's not much to go on here thus far but my money is on drywall only cracks as a result of temporary moisture changes brought about by the weather event that spawned those high winds.

One possible interpretation here is that of vertical, compressive stresses being generated at the base of the plaster and kind of bursting the corner. This might be the result of the plaster swelling downward into the slab on grade or the soil below the slab on grade swelling and pushing it up into the plaster.

It's also within the realm of possibility that the trim moulding could be involved as well, either as something swelling itself (cross grain) or as an element transferring stress between other elements experiencing volumetric fluctuation.

 

[JoshPlumSE]

Is this a single family residence, a commercial building or what? Is this the ground floor?

If there was any significant foundation settlement, I'd have expected to see some cracks in the tile flooring too. Though I suppose there are ways to install the tile that could prevent the cracking.

I wouldn't make any conclusions based on the evidence we've seen. Only recommendations that they strips off the drywall for a certain number of feet to determine if there is damage to the wall or foundation. I can't imagine they'd give much push back on this as they'll basically have do to that (at the least) to repair this damage even if it's just superficial.

 

[Tomfh]

Too early to conclude anything.

Use a laser level to see if that part has settled relative to the other areas.