How to extend ceiling over deck?

Question

Hi everyone,

Appreciate your advice and expertise!

We have a partially covered back deck that we LOVE but are looking to refresh over winter. One thing we’d love to be able to do is extend the existing covering so that the remaining portion of the deck is also covered. But not sure how to go about it. Hoping to keep the existing railing, joists etc but want to do something so that it’s still structurally sound! We’ll also then plan to install a ceiling using some Hardie flex sheeting to cover over the beams etc and maybe add some down lights and a ceiling fan etc.

Appreciate any advice on how to go about this!

Nailbag · Answer

Hi @davekatie_r

There are a few options here but they revolve around the structural strength of the existing pergola. Potentially with reinforcement the extra roof space may be able to be counter-levered which would look pretty impressive. But even if it needed additional support or even a more traditional design you're going to need a draftsperson to design it. They will be able to factor in your design requirements with the structural ones. From there you will have working plans to either tackle it yourself or get a carpenter invited,

Nailbag

Dave-1 · Answer

Evening @davekatie_r

The loading that @JacobZ has talked about is something that comes to mind high up on the list of how to.

The posts that would support the extended roof and the way the deck is currently built (That post that supports the deck in the middle looks to be a different size to the one above it supporting the roof). I would definenly be hitting up a carpenter/builder to get it right. I would be asking them if you can be the laborour because i think it would be a LOT of fun doing.

Supporting hardi plank ceiling is also something that a professional would/should assess. Extra weight being carried by the existing posts/structure is my concern.

Work arounds - Possible posts support sails or slats (from the ground up) So the new section is seperate and that way you arnt needing to touch the rails.

Instead of ceiling fans, how about wall fans?

Dave

JacobZ · Answer

Hi @davekatie_r,

Welcome to the Bunnings Workshop community, it is fantastic to have you with us.

Unfortunately, extending a roof structure, and even more so, one that is attached to a deck, isn’t typically considered a D.I.Y. job. There are wind loads, fixing methods, and engineering considerations that need to be done right to ensure it complies with building codes and council requirements. For this reason, if you are looking to build a solid structure, I would encourage you to reach out to a licenced builder or engineer for their assistance.

The process will involve adding new vertical posts to support the extended section, then installing additional beams and rafters to carry the new roof area. These need to be properly sized and securely connected to both the existing structure and the new supports so everything works together as one solid system.

You’ll also need to think about drainage. Extending the roof will mean modifying or extending the guttering and ensuring you’ve got the correct fall so water drains properly. Downpipe locations may need to be adjusted or added, and it’s important to make sure you’re not creating any water runoff issues onto the deck or nearby areas.

If you’re planning to add lighting or a ceiling fan, any electrical work will need to be carried out by a licensed electrician. It’s a good idea to plan that early so cabling can be run before the ceiling goes on.

For lining the ceiling with something like Hardie flex, the key is making sure the framing is set up to meet the installation requirements of your specific application. This will include specific batten spacing, screw spacing, as well as clearance considerations. In some cases, you may need to adjust or add to the framing to get it right and ensure the warranty is maintained.

It's definitely a project worth doing, but getting the right advice upfront and relying on the professionals when you are unsure will make all the difference.

Allow me to tag our knowledgeable members @Dave-1 and @Nailbag to see if they have any insight they can offer.

Jacob