This is the 3rd post in a series showing the demolition and replacement of the entry porch and siding at the Front Cabin. If you recall, when I demo’d the porch, I found a huge mound of earth from burrowing rats and voles making their nests! Before I rebuild the porch, I am determined to prevent the vermin from living under there again. This post will show you how to install new and replacement footings for the new front porch, and how I installed a concrete rat slab under the porch deck area to keep the rats out.
Here is a look at that insane pile of dirt found under the old porch. Haha, wow.
We also discovered holes in the siding where the mice and rats had been getting into the crawl space. Yikes!
Here’s where we are now. The front board and batten siding is fully replaced. Yes, it looks pretty much exactly as it was (lol), but I swear it’s 100% better. No more rats under the house.
Deck Ledger in Conflict with the Crawl Space Vents:
One thing I want to point out in the photo above is the crawl space vents. Since I filled the hole in the concrete stem, the crawl space vents are now shifted up between the floor joists. That works fine for venting, but this is also where the ledger board for the porch deck typically attaches to the house.
If I attached the deck ledger to the house framing, it will effectively cover the vents. So, to get around this, I am going to build the porch deck to be self supported. Instead of supporting the deck with a ledger, I will need a new back row of concrete footings and a dropped beam similar to the front dropped beam you can see in the photo above. Then, I will leave a 1/2 inch air gap between the porch deck and the siding. This will not only allow the crawl space vents to vent, but it will also prevent the siding from rotting along the ledger – assuming I can keep that 1/2 inch gap clean, which I will!
This shows the replaced siding, new vent, and patched concrete stem at the old rat hole location.
Footing Holes and Formwork:
Before placing the rat slab, I need to dig and place the concrete footings. The existing beam has pressure treated 8×8 blocks placed in the soil that are currently acting as “footings.” They are already starting to deteriorate, so I am adding new footings below the exiting beam as well. Thankfully (I guess), the 8×8 blocks are not centered below the bearing posts. So I am simply able to dig out holes for footings below the bearing posts without needing to shore the roof framing above.
Here are the dug footing holes. There are three new holes for footings along the house to support the new dropped beam. It’s hard to see the far footing hole in the photo, but it’s there.
Our local building code requires footings to be 12 inches below grade. So that’s the depth I used. They are approximately 12 inch x 12 inch square, but as you can see, more rounded out.
I am using an 8 inch diameter concrete forming tube to form the upper section of the footing. I cut the forms with a Japanese pull saw as you can see in the photo below to about 8 inches height per section.
Concrete Footings:
I had two pallets of concrete bags delivered from Home Depot so that I could get that bulk order discount. There are a number of projects that need concrete, so it made sense.
Here I am collecting bags from the pallet pile to use for the new porch footings. These are 80 pound bags. That’s about as heavy as I can maneuver around. I’m showing this as an example that you don’t need to be a burly construction dude to do this! As long as you’re reasonably fit, in good health, and persistent, you can mix and place concrete too.
I mix the concrete in this larger wheelbarrow with three 80 pound concrete bags at a time. Make sure you wear long protective gloves and safety glasses when mixing and a good face mask for the concrete dust.
Here I am placing a new concrete footing for the new dropped beam. You can see the tube formwork for the upper section. I also placed a Simpson BC post cap in the concrete to secure the new dropped beam. You can see I am using a level and a small pressure treated block to make sure the footing and the hardware is the correct height for a level beam.
These are the finished footings for the front porch deck. The new dropped beam will be very close to the house and support the back of the deck. This allows us to avoid a ledger connected to the house.
Dig & Prep for the Rat Slab Under the Porch Deck:
Now that the footings are in, its time to dig for the rat slab. A rat slab is a non-structural concrete slab that is typically used under homes in the crawl space. It keeps things cleaner down there and does prevent rats from burrowing into your crawl space. That’s exactly what I want under the porch deck.
To keep things simple, I am placing the rat slab where I really need it from the house to the farthest dropped beam. I am also digging a dropped edge or thickened perimeter for that rat slab in the hopes that a dropped edge will prevents rats from burrowing under the slab. Begone rats! I really mean it this time!
Here I am digging the thickened edge along the dropped beam.
This is the finished dig for the rat slab. You can see the trench for the thickened edge of the rat slab.
Since this rat slab is non-structural, it doesn’t NEED reinforcement. But I had some galvanized chicken wire laying around, so I laid that down to provide some connectivity in the concrete. Here you can see the chicken wire.
Place Concrete for the Rat Slab Under the Porch Deck:
Now let’s place the concrete! I say “place” because I really do place it, not pour it. Concrete shouldn’t be soupy if you’re just using water. You can add plastizing additives or use a more flow-able mix to get the concrete mix soupier, but that’s now what I am using here.
These are the completed footings and the rat slab under the porch deck. Whew! The rat slab used about thirty 80 pound bags of concrete, all placed in one day. I honestly didn’t think I’d be able to mix and place that many bags in one day. But I felt OK at the half-way mark and decided to just keep going. I was very tired and hungry at then end, but am so glad that’s done!
I would like to say a little non-secular prayer/blessing for this rat slab in hopes that all this hard work pays off. ***Bless this porch and keep the rats away from under the deck and out of the crawl space.***
If this doesn’t work, well, I might have a little cry, reassess my life, but then, of course, try again. Thanks for following along on this journey with me. Hope this post was helpful or at least somewhat entertaining.
