How to Cement Your Chimney Cap

What You'll Need

Putting cement onto a chimney cap is one way to prevent heat from escaping through the top of the cap. It also ensures that the cap is getting the best device to ensure that rain, animals and debris don't fall down your chimney. The cap prevents sparks and dirt, and you can cap a chimney by either installing a metal cage device over the top, or you can use cement like a crown, to protect the entire flue. This might seem like a difficult task, and if you have no head for heights it might not be the take for you, but for most people, once you know what to do, this job should not take you more than a few minutes. Getting this job done doesn’t need the assistance of a professional if you have some basic home improvement skills. All you have to do is follow a few simple guidelines to get the job done quickly and easily.

Step 1 – Prepare the Chimney

The first step is to ensure that the chimney is got ready for the cement cap. Remove any mortar which is loose, or has been previously used for a different chimney cap. You should sweep off as much of the excess mortar as you can using a hard-bristled brush. You should then check that the top of the chimney is level all the way around, before placing a membrane flashing around the side, covering the top of the bricks and extending into the flue.

Step 2 – Place the Frame

Next you will have to build a joint around the flue, so that you have a support for the chimney cap as it is drying. It is best to use plastic, as this can be easily pulled away once the cement has completely dried. Once this is build, use your lumber to create a tougher frame for the cement. The wood should rise slightly above where you intend the top of the cap to be. You may wish to cut a notch in the top of each piece of timber, which will allow rain to travel away from the chimney. Screw the boards together so that it fits around the top of your chimney bricks. Place another layer of timber around the top of the chimney, so that the cap will be supported.

Step 3 – Add the Cement

Once that is completed, you will have to add the cement. Mix up your cement powder, and use a litle bit of caulk around the top of the chimney to moisten it. Pour the cement into the frame's space, so that the cement flows right to the edges of the frame. Smooth the top of the cement until it is flat, and hen leave to dry. Once the cement has had a chance to partially dry, perhaps 24 hours, remove the frame, and caulk around the flue, and then add waterproofing at the edges to ensure that the chimney cap will be completely dry.