Pouring Concrete Chimney Cap

Chimney crown also termed as chimney cap or chimney top plate is a cover provided on the top of chimney chase to prevent the entrance of rainwater into the chimney.

Pouring concrete chimney cap.

The stones in concrete are what really give it its strength. Chimney weather cap or chimney crown construction suggestions. 3 rebar leaving it 2 inches in from the edges of the form. My solution was to pour the cap in place and then remove the formwork with the help of my car jack.

I ran into a chimney sweep who explained that the reason so many caps crack is that since the mason is up there finishing the top of the chimney and he s got a batch of mortar and he s all set up to mix mortar he creates the cap out of mortar which doesn t last as well when exposed horizontally as it does when exposed vertically. This article describes the construction of the concrete crown or weather cap found at the top of masonry chimneys and flues. The mortar mix rarely has any stones in it. A chimney cap sometimes referred to as a crown is a reinforced concrete cap placed over the top of a brick and mortar chimney.

This sweep said that when he does a replacement he. This article series illustrates common chimney cap crown types choices defects and we cite pertinent chimney top cap crown building codes standards for fire and other safety concerns. Then fill the form with concrete. Mix the concrete you will pour into the form using small aggregate.

The chimney crown should be made using real concrete not the mortar mix used for the brick or stone. I decided to pour a concrete cap for the chimney knowing that the primary challenge lay in getting the thing to the top of our 2 1 2 story house. Dampen the chimney brick with water and pour 1 inch of concrete into the form. Otherwise the concrete will not bond to the brick surfaces.

Contents bia recommendations construction of concrete chimney crown1. If the chimney has clay flue liners the crown or top concrete material should never touch the flue liners.