Looking to extend my front porch

[Jkyeoman]

Hi everyone, as the title  says I’m looking to extend my front porch; currently have a cement slab on brick approx 6.5x2.1m 550mm high and looking to extend it 1.7m to finish in line with the front of the house and put a veranda over the top and tile. Not sure what the best way to go about it, my thoughts are -

build it as a seperate structure but how do you prep that so you can tile over it

Run a ledger board from the edge of the slab or brickwork and extend as a single structure

or rip the slab out and start fresh, wife not keen on this option and it’s not my idea of fun lol.

I have attached a couple photos for what’s it’s worth, but if a bomb site (mid Reno)

 

 

[MitchellMc]

Hi @Jkyeoman,

The two options for construction that strike me as viable would be to either replicate the exiting slab structure and have concrete poured or to create a deck-like structure out of timber and install James Hardie 2400 x 1200 x 15mm 2.88m² HardiePanel Flooring. Here's the installation guide for your reference. 

I'd highly encourage you to connect the two structures with a ledger board mechanically. Otherwise, you'll create a join with movement, and your tile grout will constantly crack there. Ideally, if there is enough room, you should create the new structure out of timber and clad over both the slab and the timber with HardiePanel, then tile over that. In this scenario, you'll be less likely to experience any issue associated with the two structures. From your images, it looks like the door sill is fairly low, and the 15mm sheet, glue and tiles might be too thick to accommodate.

If you are tiling over the slab, I see no real benefit in removing it. Once tiled, you can clad the sides of it, and you'd never know it was there underneath. 

This sounds like a great project, and I look forward to seeing your progression. Please let me know if you have questions about what I have described.

Mitchell

[Jkyeoman]

thanks @MitchellMc for the info. I was a bit hesitant about building a separate structure due to possibility of movement. will go ahead and attach a ledger board and build out from that. My first thought was to build a frame over the existing slab, panel and tile but the gap under the door sill to the existing slab is 45mm so i am guessing that would be too low unless there is a low profile joist that is available for this type of situation.

[MitchellMc]

My thoughts were to lay the James Hardie 2400 x 1200 x 15mm 2.88m² HardiePanel Flooring directly onto the concrete section @Jkyeoman. The timber frame would only be needed to create the new structure. The boards would continue out and off the concrete structure onto the timber frame that's height would be flush with the top of the concrete. That way, the concrete area is only raised 15mm before tiling.

Mitchell

[Jkyeoman]

yeah sorry @MitchellMc my brain likes to overcomplicate things. Just one more question and I think I’m set… just with the fall. the current slab is 2180mm wide and the height difference at the edge of the slab is approx 55mm, which if I have calculated correctly makes it 1.4deg slope??  I just continue this with the new deck section.

[Jkyeoman]

Sorry there is another question, just read the install guide for the compressed panel, but doesn't advise on how to fix the sheet to a cement slab. What would be the best way to go about this?

[MitchellMc]

@Jkyeoman,

The slope of the concrete area sounds adequate, and I'd continue it for the new section. Just make sure the new section falls 26mm per meter.

After chatting with the team at James Hardie, it looks like they require a breathable cavity under the HardiePanel. This means it can't be fixed directly to the slab. I'd go with the original idea of having the board on the new timber structure flush with the slab and tiling over the concrete area onto the panels.

Mitchell

[Jkyeoman]

thanks for the info; I assume that the James Hardie secura exterior floorings would also need an air gap? I did like the idea of sheeting over the old and new section; would have given me a really good flat surface to work from.

[MitchellMc]

@Jkyeoman,

All indications in the installation manual for the Secura floorings suggest it must be installed over a timber frame. I did ask the James Hardie technical support if any of their other products would be suitable for direct fixing to concrete, and they advised that none of them were.

I understand the disappointment as a perfectly flat surface would have been ideal to work with.

Mitchell