The Brew Cabin

Posted: **Thu Sep 05, 2019 3:08 pm**

Hello,

I am looking for advise on how to lay some handmade terracotta paving particularly in regards to how they should be jointed.

They are 40mm x 150 x 300mm.

Inside we have 20mm thick versions of the same brick laid on concrete screed with 3mm gap.

The builder used a mortar gun with his own mix to joint them.

The landscaping companies all want to use brush/wash in jointing materials (EasyJoint etc) to joint the outside bricks. We are worried about staining and how this will work with a small 3mm gap.

Also what would people recommend they be laid on sand or concrete screed?

Posted: **Sat Sep 07, 2019 9:43 pm**

Terracotta, the genuine stuff, not ersatz terracotta that's really wet-cast concrete, is an incredibly thirsty material, so when it's jointed with any slurry mortar, whether cement or resin, there's a huge risk of the binder being absorbed into the body of the paving and forming a permanent stain.

The key to success would be to abso-bloody-lutely saturate the terracotta with clean water before placing the slurry, and then use plenty of additional water to keep it moving about, and to wash off the surplus. I've seen this work well with cement slurries and with 2-part resin slurries, as long as the jointing is undertaken thoroughly and speedily.

Sadly, I've seen staining problems with 1-part, oil-doped resin mortars (polymerics) where the oil gets gobbled up by the terracotta no matter how much water is applied, and it can take a season or longer for the effect to weather out.

Gun jointing is a good alternative, if your back can take the strain, but I'd look to use a purpose-made gun mortar rather than attempt to knock-up something ad hoc.

Pre-treating the terracotta with a suitable sealant (or similar) can often help minimise problems with absorption. I personally don't like the "varnished look" that comes with most sealants, so I'd opt for an 'invisible' treatment, that provides the benefits of reduced absorption and some stain protection without altering the appearance of the paving.

The Brew Cabin

Joint options for handmade terracotta paving - Need opinions on