Question for anyone with brick hearth pad building experience: what should our joints be filled with? Mortar or thin set? We used thin set for adhering the brick to the Durock with a 1/4” notched trowel - spritzed with water first - which worked great and the bricks are very firmly adhered. Due to the required dimensions of our hearth pad and brick size/spacing, we have a little over 1/2” gap between all of our bricks. We are worried the thin set won’t dry when it’s applied so thick and that it won’t provide enough strength to keep the bricks in place over the years as people stand on the hearth pad. We found Rapid Set Mortar Mix at HD and are wondering if that would be better? Or another type of standard mortar? We are wary of using mortar because of another thread on here where a guy said his S type mortar didn’t adhere his bricks... that being said our bricks are already adhered, we just need to fill the joints. Seems like thin set is best for it’s fine sand/adhesive properties whereas mortar is best for filling larger gaps and structural strength? Is that right? For reference, here’s a pic of the hearth pad currently and the thin set we used. We have a 300 lb Supreme Vision that will go on top of it. Bricks are at least 100 years old - from the fireplace we removed, hence the rustic look - not sure if that makes a difference in joint-filling. Thanks for the help!