Vertical Cracking in Wall

[Mark-UK]

I have recently built a block shed (single skin) with a timber roof.

The walls were completed in October 2017. Today I found a crack in one of the walls. It starts at the top, and it goes halfway down. It's cracked on the inside as well as the outside.

The floor around that area looks solid. It's built predominantly on clay and the footings were filled concrete.

Weird thing is that the crack has occurred directly behind one of the support pillars:

Here's the outside:

This is how far down it goes (about halfway):

The crack is 1.5mm wide at the widest gap, otherwise, it is 1mm wide (inside and out).

Truth be told I'm new to all of this and I am quite worried. I've put a lot of time, effort, and money into my shed. Can someone advise me, please?

Thanks all.

 

[^woody^]

Contraction. Mortar mix too strong.

 

[Mark-UK]

Contraction. Mortar mix too strong.

Thanks for the reply Woody.

Is it serious? Should I be worried?

 

[^woody^]

Is not a structural issue, but any crack in render needs dealing with as it lets in water and degrades the render over time.

Easiest thing to do is gouge it a little and fill it with a clear silicone, or if you are painting it, use a polymer or polysulphide product.

Monitor it.

 

[Mark-UK]

Is not a structural issue, but any crack in render needs dealing with as it lets in water and degrades the render over time.

Easiest thing to do is gouge it a little and fill it with a clear silicone, or if you are painting it, use a polymer or polysulphide product.

Monitor it.

That's a relief! Thanks Woody, I appreciate the advice.

Yes, I'll be painting it (soon) so I'll get on to it.

At the risk of being a pain, can you recommend a good product for filling in please?

Thanks again.

 

[^woody^]

The problem with cracked render, and cracked walls is that there will always be a bit more movement. So you need a flexible mastic, and one that will be paintable. So look for a polymer based mastic/sealant. Some are marked as adhesive/sealant, but look for the polymer word, and not silicone. Or a polysulphide mastic. Avoid anything that says acrylic.

You'll pay about £5 - £8. Any one will.

When you fill the crack, dip a flat bit of metal or plastic in soapy water and scrap this along the surface to flatten it out.

 

[Mark-UK]

The problem with cracked render, and cracked walls is that there will always be a bit more movement. So you need a flexible mastic, and one that will be paintable. So look for a polymer based mastic/sealant. Some are marked as adhesive/sealant, but look for the polymer word, and not silicone. Or a polysulphide mastic. Avoid anything that says acrylic.

You'll pay about £5 - £8. Any one will.

When you fill the crack, dip a flat bit of metal or plastic in soapy water and scrap this along the surface to flatten it out.

Brilliant!

Thanks very much Woody. I appreciate all the help.

 

[Mark-UK]

This one is paintable, flexible, and polymer based.

www.sealantsonline.co.uk/ProductGrp/Geocel-201-polymer-paintable-mastic-sealant

Will that work? Not sure what it means when it says "One part polymer" though.

 

[^woody^]

Yes that's the type.

 

[Mark-UK]

Yes that's the type.

Awesome!

Thanks Woody (again)

 

[Mark-UK]

Will this gun to the trick?

www.screwfix.com/p/p-c-cox-easiflow-gun/79714

The sealant is in a 380ml tube and that gun caters for 310 to 400ml