How To Pour Concrete Footings Underneath an Present Concrete Patio

Concrete footings are an vital a part of a construction like a pergola or a deck, and so they present the strong basis and assist for the remainder of the construction. Get set up ideas and recommendation on pouring concrete footings for a pergola or deck beneath an present patio from the consultants right here.

Have to pour a brand new concrete slab? Discover ways to DIY your personal concrete patio right here.

In case your patio simply wants an improve, listed here are 9 methods to replace your concrete slab (and sure, you’ll be able to paint it!)

Pouring The Concrete Footings in Existing Patio (With The Plywood to Protect the Concrete Pad)

You don’t have to tear up your present concrete for a sturdy basis to your subsequent patio undertaking. 

Whenever you’re prepared so as to add a pergola or a deck to your concrete patio, you’ll be able to hold the concrete slab AND pour new footings! I’m exhibiting you ways — and you may see the attractive pergola I construct on prime of those footings right here.

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What’s a Concrete Footing?

A concrete footing is the underside a part of a basis. For outside tasks like a pergola or a deck, footings are used to anchor the posts securely to the bottom. Footings are important to make sure that the construction has a powerful basis and may maintain as much as common use and inclement climate.

Deck and pergola footings are usually set deep into the bottom for added stability. There are alternatives to put in a pergola with out footings, however for a big undertaking like this, I all the time advocate the longevity and security of in-ground footings.

In Ground Concrete Piers
An in-ground concrete pier like this deck makes use of is an instance of a footing.

Varieties of Put up Footings

For a deck or pergola, there are various choices for laying the footings and putting in the posts. Right here’s a quick overview of the three commonplace deck and pergola footing choices — and bear in mind to examine together with your native council or workplace to make sure that your footings will meet constructing code.

In-ground footings with buried submit

It is a quite common footing set up, and may be finished with or and not using a concrete block on the backside. Lauren and Brett used a buried submit footing for the viral hearth pit pergola with swings.

1a How To Build A Backyard Fire Pit Pergola For Swings LWH Blog For Remodelaholic 050058
Giant pergola with swings, utilizing in-ground buried concrete footings // LWH Weblog for Remodelaholic

For this footing set up, a deep gap is dug and the submit is positioned within the gap, leveled and plumbed, after which the outlet is crammed with concrete or soil.

For added safety (and to fulfill code in lots of areas), one of these footing usually features a concrete block (both pre-made or recent poured) on the backside of the footing gap.

Buried footing like this requires lumber handled for floor contact (pressure-treated).

This additionally limits the peak of the pergola or deck posts (or will increase the price of a tall pergola, to purchase longer posts) since a part of the posts are buried within the floor.

Premade deck footing blocks

Premade deck footings blocks (pier blocks) could be a good possibility for a small deck that’s not connected to the home, like our outdoor pool deck. Deck blocks are NOT really useful to be used as pergola footings.

Pool Deck Model Remodelaholic
Pool deck for an out of doors above-ground pool, utilizing precast deck blocks // Remodelaholic

A poured footing will probably be stronger and last more than utilizing deck blocks, particularly in areas with extreme climate, so I usually advocate going that route. Some codes don’t enable utilizing pier blocks for sure tasks, so once more, make sure to examine your native rules.

To make use of pre-poured deck blocks (piers), the soil is compacted and leveled to supply a basis for the block. Then the block is positioned and leveled and the submit is positioned within the block, the place it’s held in place by the form of the concrete block (and gravity/the burden of the deck).

Deck blocks don’t require lumber handled for soil contact, however they’re restricted within the sizes of lumber you should use and the energy of the footing.

Poured concrete footings

For a professional-level set up and the perfect sturdiness, go along with poured concrete pier footings!

Timber DIY Pergola with Concrete Footings Poured Beneath Existing Patio
timber pergola construct utilizing poured concrete footings beneath present concrete patio // Remodelaholic

In a poured concrete footing set up, a gap is dug to regulation dimension, which is able to relying on the dimensions of the submit, the soil content material, and the depth of the frost line within the space. Then, concrete is poured within the gap, both immediately within the gap or through the use of a concrete tube kind, to kind the footing pier.

A submit bracket may be both set within the moist concrete earlier than it cures, or connected to the concrete pier utilizing bolts after the footing has cured (like I did with this huge lovely pergola.)

Poured concrete footings are the perfect methodology of including concrete footings to an present concrete pad.

When to get a allow for a deck or pergola

Native constructing codes differ, so make sure to examine together with your native council, metropolis workplace, or owners affiliation for particular rules. Basically, you’ll NOT want a allow when:

  • The deck is lower than 30″ above grade (above the bottom).
  • The deck or pergola is just not connected to the home.
  • The deck or pergola is beneath 200 sq. toes.
  • The deck or pergola is in a personal yard and never close to the property line.

Due to the dimensions of the pergola (simply over 200 sq. toes), I had the native constructing division approve the design and utilized for a constructing allow earlier than I acquired a began.

What’s your native Frost Depth?

Frost line depth is the depth to which the bottom freezes in the course of the winter. Footings ought to usually be a minimum of 12″ beneath the frost depth to stop heaving (shifting up) in the course of the coldest months.

Frost Depth Lines From NSIDC
frost depth map courtesy NSIDC | credit score: Neil Davis

Footing Dimensions

The size of your submit footings will differ primarily based on the construction dimensions, native frost depth, and native soil circumstances.

For this undertaking, the footings are going to be 8″ extensive and greater than 30″ deep.  The dimensions would differ relying on the kind of construction you’d be constructing.

You would want to first seek the advice of with an engineer and have plans accepted earlier than putting in your footings to ensure they’re sufficiently big to your undertaking.

BEFORE YOU DIG: Name 811 to have the utilities marked. Don’t dig till you already know the place the traces are!

Web site Preparation

If you end up pouring in-ground submit footings, you need to ensure that the bottom is steady and well-compacted previous to digging the footing holes.

For pouring concrete footings in an present concrete patio — that work is already finished for the patio basis, so that you simply have to clear the patio.

Supplies and Instruments to Pour Concrete Footings for a Pergola or Deck

When you’ve determined the format of your pergola or deck posts (and consulted an engineer about correct placement, depth, and reinforcement), you’ll want these supplies and touls to pour the concrete footings beneath the prevailing concrete slab.



Do you know? You may lease instruments like an auger, angle grinder, hammer drill, and cement mixer from your local Home Depot.

Step by Step: How To Pour Concrete Footings Underneath an Present Concrete Patio

Step 1: Lay Out The Footing Areas

Primarily based in your design, find the location of footings and mark the middle of every footing with an X.

How To Mark Pergola Footing Locations On A Concrete Patio Remodelaholic

I like to make use of white tape caught on the concrete as a result of it makes the marks simpler to see and is a greater writing floor. Then, use an axe and hammer to mark the middle of the of X.

Keep Project Square 3 4 5 Rule Remodelaholic

Hold the format sq. with the three – 4 – 5 Rule. Use your tape measure to measure out 3 toes from the nook a technique (x-axis) and 4 toes from the nook the opposite method (y-axis), and, if it’s sq., if you measure the 2 markings at a diagonal the space will probably be 5 toes. (Keep in mind the Pythagorean theorem? 🤓)

Step 2: Minimize Holes within the Present Concrete

There are 2 choices for slicing holes in a concrete slab: an angle grinder and hammer drill, or a concrete gap press (bore press).

Angle Grinder And Hammer Drill Cut Hole In Concrete, Remodelaholic
slicing concrete utilizing an angle grinder and hammer drill

Angle Grinder and Hammer Drill

Chopping a gap in concrete utilizing an angle grinder and hammer drill takes a while, however prices lower than renting a concrete gap drill.

You’ll rating the sides of the sq. gap with the grinder, after which use the hammer drill to interrupt up the concrete into items to take away it.

It is a good possibility for slicing a 10-12 sq. inch extensive gap.

02 Cutting Concrete Slab

Concrete Gap Drill (Bore Press)

A concrete gap drill will lower a pleasant clear round gap within the concrete slab. I desire this once I can as a result of it saves time and offers a really clear lower edge.

Renting a concrete gap drill usually additionally means hiring the skilled who runs the drill. Native costs will differ, and in my space of central Utah, I paid $100 per gap. Undoubtedly price it for the time and mess saved!

After the core was lower, I used a hammer drill to interrupt up the core to take away it from the outlet.

Word that the concrete gap drill does require one further gap to anchor the massive drill, however that’s simply patched after.

BEFORE YOU DIG: Name 811 to have the utilities marked. Don’t dig till you already know the place the traces are!

Step 3: Dig the Holes Beneath the Concrete Patio

Use a submit gap digger and/or auger to take away the filth to dig the holes.

03 Digging Post Holes

I deliberate to lease an auger, however the soil beneath the patio was a very good soil: loamy clay soil and simple to dig by hand. So I dug the holes manually with the submit gap digger. It took me about half-hour per gap to dig my 30-inch deep holes.

If the soil had been rocky, prefer it usually is in my space, I’d have wanted to lease an auger.

If the soil had been sandy and fewer steady, I’d have additionally wanted so as to add a concrete tube (sonotube) for added stability for the footing.

Step 4: Droop Rebar Earlier than the Pour

This pergola required footings with 28 inch #4 rebar within the middle, 3 inches above the underside of the outlet for added tensile energy. (Keep in mind, seek the advice of an expert engineer and your native code to know what rebar is required to your footings.)

Suspended Rebar For Pergola Poured Concrete Footings In An Existing Patio, Remodelaholic

The best solution to place the rebar is to put a bit of scrap wooden throughout the outlet and droop the rebar utilizing baling wire. This holds it in place for the pour and is simple to take away.

BONUS: Add Watering System

This shopper knew they wished to have hanging planters on the pergola, so earlier than we poured the footings, the landscaper stopped by to run some pipe from the primary sprinkler system up via the footing gap. This made it simple for them to tie a drip system for hanging planters into their common watering automation.

Add Drain Pipe Before Pouring Pergola Footings To Water Hanging Planters Remodelaholic

Step 5: Cross Inspection Earlier than Pouring

As soon as all of the items of rebar the place suspended, I used to be in a position to name and have the inspector come and approve the holes.

Relying in your undertaking dimension and native space codes, it’s possible you’ll or might not want the holes inspected. Due to the dimensions of this pergola, I did.

I dug my holes barely larger than required to be on the protected facet, and, after clearing some particles from a beforehand buried railroad tie, handed inspection.

Once more, soil circumstances (similar to sand) might require a sonotube (concrete tube) to create a extra uniform concrete footing, if soil is much less steady or sandy.

Step 6: Defend the Concrete Pad

Earlier than you combine and pour the concrete within the gap, make sure to defend the prevailing concrete pad! This hold your patio clear and can make the distinction between your completed footings trying like an inexperienced DIY job and searching like a professional.

04 Pouring The Concrete With The Plywood

In a bit of plywood, lower a gap the identical dimension as your concrete gap, and place the plywood immediately over the outlet. Then pour the concrete via the plywood gap into your footing.

Step 7: Combine and Pour Concrete

You may lease a concrete mixer or combine by hand like we did in a wheelbarrow.

I used an internet concrete calculator to determine what number of whole baggage we would have liked. We ended up utilizing about 2.5 80# baggage of concrete per gap, and every gap took about half-hour to combine and pour.

Simply observe the directions on the bag so as to add the water to the fitting consistency. Then pour and scoop the concrete into the outlet. The plywood will hold the splashback from getting on the patio!

Because the concrete will get to the highest of the footing gap, take away the plywood and thoroughly clean out the highest of the footing.

Tip: Pouring concrete into dry soil might pull the moisture from the concrete and lead to a weakened treatment. If the soil in your footing gap may be very dry, think about dampening it (however not sufficient to create standing water within the gap), or utilizing a concrete tube. Correctly moistened soil (or a ready concrete tube) will hold cracks to a minimal and provides the strongest pour.

Step 8: Stage the Concrete

After the concrete has cured a bit, you need to degree and clean the highest of your poured footing, to match the concrete patio degree and end.

Trowel Top Of Poured Concrete Footings In An Existing Concrete Patio, Remodelaholic

Use a small trowel to degree the highest of the footing with the concrete patio and produce the “cream” to the highest. Clean out the highest of the footing.

Concrete “cream” is prime layer of concrete that’s main smoother cement with no gravel combination seen. Bringing it to the highest offers you a very nice trying end and helps the floor energy.

Step 9: Connect Put up Bases

Now you’re prepared to connect submit bases to your deck, gazebo, or pergola to your DIY concrete pier footings. For this pergola, I used these Simpson Strong Tie Concealed Post Basessee the remainder of the pergola construct particulars right here.

Drilling Bracket Holes In Concrete


Pouring concrete footings beneath your present patio is an effective way to have the foundational stability you could add a pergola or deck and make your patio an incredible household hangout!

Concrete Footing FAQ  

How deep ought to concrete footings be?

Concrete footings want to increase beneath the frost line. See the map and hyperlinks above to find out the frost depth to your space.

Do I would like rebar in footings?

Most footings require a minimum of some rebar reinforcement. Examine your native constructing codes and seek the advice of with a structural engineer to your undertaking.

How do I calculate concrete footings?

Figuring out the quantity and placement of concrete footings for a pergola or deck will rely upon the dimensions and format of the deck and width of your posts.

Seek the advice of an engineer and your native constructing code workplace to make sure you have satisfactory assist to your construction.

Is a footer vital on a concrete slab?

To construct on prime of a concrete slab, you should use a bracket designed for that function to anchor your pergola, gazebo, or deck straight to the prevailing concrete slab, in the event you desire that over a footer. The slab will usually must be crack-free and a minimum of 4″ thick with a really useful 12″ whole depth on the skin edge.

A concrete footer like we confirmed above will provide you with way more energy and sturdiness, since it’s dug a lot deeper into the bottom than the concrete slab is poured.

Pouring a concrete slab? For a patio, driveway or sidewalk, no footer is required. For a basis of a house, storage, or shed, YES you have to a footer for the muse. That’s not what this tutorial covers 🙂

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How To Pour Concrete Footings In An Existing Patio To Build A Large Wood Pergola, Remodelaholic

I’m the husband of the superb Cassity of Remodelaholic. I like to drawback clear up and to design and construct issues inside and out of doors the home to make life higher. I’m an expert Panorama Architect by commerce and love the outside.