Why Would A Fireplace Crack After Installation?
Background to this article: We were recently contacted by a lady who purchased a limestone fire surround from a local showroom (This faulty product has nothing to do with us) and just after installation a large crack appeared near the back panel. The lady asked for advice and wondered if we had any explanation why a crack would appear just after installationWhy would a fire surround crack?
1. The majority of showrooms, fitters and fireplace specialists would obviously try and under exaggerate the fact that a crack has appeared. Unfortunately many specialists would try and argue the fact that a “crack can appear against the veining of the limestone”& that this is a perfectly normal occurrence ... the truth is obviously different, & a fire surround should not crack
2. Below is the image we were sent showing the crack in the fire surround 
• The images shown seem so imply a large crack • In this case, the crack appeared "after" the fireplace was fitted & a few days later Intuitively the fact that the crack appeared a few days after installation makes sense, as no customer would have signed off a work sheet if the fire surround had the crack shown
Possible explanation:
• (a) Certain gas fires have an extremely high heat output & efficiency rate •
(b) A crack can be caused due to excessive heat build up behind the back panel • (c) This would happen if the chimney was not filled or sealed to the same distance/size as the opening within the back panel
• Example:
• The standard cut out in the back panel is 16.25 inches wide & 22.25 inches high. • Hence if your chimney had an opening 20 inches wide and 25 inches high (for example) and this wasn’t filled/sealed to the same size as the opening within the back panel, then there would be a build up of heat behind the back panel that would eventually escape by forming a crack
