How To Replace a Wood Porch Post with a PVC Post
How to Replace a Wood Porch Post with a PVC Porch Post
A Step-by-Step Guide to Upgrading Porch Columns
Replacing a rotted wood porch post with a PVC post is a great way to reduce future maintenance while maintaining the appearance of your home’s exterior. The project isn’t complicated, but it does require safely supporting the porch roof while the existing post is removed and replaced.
Here’s the process I use.
Tools and Materials Needed
- PVC porch post sized to match the existing post
- Decorative PVC post base and cap (recommended to conceal mounting brackets)
- Plastic shims
- Galvanized mounting brackets (top and bottom)
- Galvanized post standoffs
- Hydraulic bottle jack
- 2×4 lumber for temporary supports
- Tape measure
- Circular saw
- Reciprocating saw
- 48-inch level
- Drill/driver
- Exterior-grade fasteners
- Tapcon screws or wedge anchors
- Exterior caulk and caulking gun
Pro Tip
Many PVC column manufacturers offer top and bottom mounting brackets designed specifically for their columns. If available, purchase them. Decorative base and cap moldings do an excellent job of hiding the brackets and creating a clean finished appearance.
Step 1: Measure the Existing Posts
Before removing anything, measure both existing porch posts and record the dimensions.
Next, check the porch beam with a level. If the beam is out of level, identify which post is carrying more weight. Replace the higher post first.
Step 2: Build a Temporary Jack Post
Cut two 2x4s and screw them together to create a temporary 4×4 support post.
Place a protective 2×4 flat against the underside of the porch beam to spread the load and prevent damage.
Position the hydraulic jack beneath the support post and slowly lift the porch beam.
Important
Only raise the beam enough to relieve pressure from the existing post. Typically, you only need enough clearance to slide a reciprocating saw blade into the joint.
Over-jacking can damage trim, roofing materials, or structural connections.
Step 3: Install Temporary Bracing
Build a second temporary 4×4 support from two 2x4s and install it next to the jack post.
To be honest, I often leave the jack in place and skip this step on smaller porch roofs, but adding temporary bracing provides an extra margin of safety.
Step 4: Remove the Existing Wood Post
Use a reciprocating saw to cut any nails, screws, or fasteners connecting the post to the beam and porch floor.
Sometimes it’s easier to cut the post in the middle and remove it in sections.
Once all fasteners are removed, carefully pull the post free.
Step 5: Cut and Test-Fit the PVC Post
Measure from the underside of the porch beam to the porch floor.
Cut the PVC post to length and dry-fit it into position.
Verify that the post fits snugly and sits plumb.
Step 6: Install the PVC Porch Post
Position the post in place and use a level to ensure it is perfectly plumb.
I typically position the top of the post first, then plumb it down to the concrete. Once the location is confirmed, I mark both sides of the post on the concrete as reference points.
Install the mounting brackets and secure the post according to the manufacturer’s recommendations.
Pre-drill pilot holes whenever fastening through PVC to prevent cracking.
Step 7: Lower the Roof onto the New Post
Slowly release the jack and transfer the porch roof load onto the new PVC post.
Check the post for plumb and make adjustments as needed using plastic shims.
Before replacing the second post, recheck the porch beam with a level. This is your opportunity to correct any sag and bring the roof closer to level.
If adjustments are needed, move the jack and raise the beam slightly. Measure for the second post and cut it accordingly.
Pro Tip
I typically jack the roof approximately 1/4 inch higher than needed to make installation easier. Once the post is secured, slowly lower the load onto the new column.
Step 8: Finish the Installation
Apply exterior-grade caulk where the post meets the beam and porch floor.
Install any decorative base or cap trim pieces to conceal brackets and fasteners.
Most PVC porch posts are maintenance-free and do not require painting, although they can be painted if desired.
Final Thoughts
PVC porch posts are an excellent upgrade for homeowners dealing with rot, moisture damage, or ongoing maintenance issues. By taking the time to properly support the porch roof and carefully measure each replacement post, you can achieve a clean, professional-looking installation that should last for decades.
