How to Pull Together a Sagging Wood Deck

In this 3rd installment of the Sagging Wood Deck Repair series, I stabilize the wood deck with a cable winch to prevent it from pulling further apart before replacing the 6×6 wood deck post and concrete footer. This project is continued from How to Sister a Wood Deck Post for Beam Splice Support.

How to Pull Together a Sagging Wood Deck

As explained in Part 1 of this series, the floor plan of my home was extended by the home builder with an 8 feet long deck addition on the right side of the guard post in the following photo.

Remove the 4×4 Guard Post

I need to pull the deck together and reinforce the 2×10 rim joists before replacing the 6×6 deck post. I began by removing the 4×4 guard post at the beam splice. Note how the guard post is notched. Notching is no longer allowed per the Georgia Amendments Prescriptive Deck Details based on the 2012 International Residential Code.

Wood Deck - Guard Post Notching No Longer Allowed — Wood Deck – Guard Post Notching No Longer Allowed

Pull Up the Deck Board

Next I pulled up the deck board above the beam splice:

Deck Repair - Pulling up Deck Board — Deck Repair – Pulling up Deck Board

The 2×10 rim joists are now revealed. The deck sag is quite pronounced:

Sagging Wood Deck Inspection

Closeup of how much the 2×10 rim joists (or “beams”) and 2×8 sister joist have separated from the main deck. I think it wouldn’t have been too many more years before the deck collapsed if not repaired!

Wood Deck Repair - Joists Pulling Apart — Wood Deck Repair – Joists Pulling Apart

View from below the deck showing the sister block installed in Part 2:

Wood Deck Repair - Sister Block Joist Support Details — Wood Deck Repair – Sister Block Joist Support Details

Pull the Deck Together with a Cable Winch

I installed a Come-Along cable winch puller anchored to two 1/2 inch galvanized through-bolts with washers and nuts set in the 2×10 beams. The reasons for the cable winch are:

To stabilize the deck when I replace the left corner deck post.
To pull the deck together for final fastening with steel angles and structural wood screws.

Wood Deck Repair - Come Along Cable Winch Puller — Wood Deck Repair – Come Along Cable Winch Puller

I tensioned the cable winch only a bit for now. View of the cable winch, joist splice and sister block looking down:

Wood Deck Repair - Improper Beam Splice — Wood Deck Repair – Improper Beam Splice

Reinforce the Deck Joist Connections

The inside 2×10 rim joist is nailed to the end of the 2×8 sister joist. I verified this by sliding a thin hacksaw blade between the boards and locating the nails. I cut the nails with a Sawzall reciprocating saw so I could refasten the 2×8 sister joist:

Wood Deck Repair - Sawing Joist Nails with Sawzall — Wood Deck Repair – Sawing Joist Nails with Sawzall

You may be wondering how I’ll fasten the 2×10 rim joists to the deck 2×8 sister joist as I’ve sawn through the nails. I’ll install a Simpson Strong-Tie ML26Z Angle with SDS 1/4 by 2-1/2 inch structural screws in addition to two FastenMaster LedgerLok 5 inch screws driven in at an angle outside the 2×10 joists:

Simpson Strong-Tie ML26Z Angle and SDS Structural Screws

This photo is from much later in the project. I’ve also brushed on a coat of the Copper-Green Brown Wood Preservative:

Wood Deck Repair - Simpson Strong Tie ML26Z Angle on Joists — Wood Deck Repair – Simpson Strong Tie ML26Z Angle on Joists

I fastened the 2×8 sister joist to the 2×10 outside joist of the original deck with four FastenMaster HeadLok screws. The “SpiderDrive” screw is similar to a Torx drive and the bit won’t back out under high torque. A SpiderDrive bit is included with the box and I bought extra bits in case I misplace one.

Wood Deck Repair - FastenMaster HeadLok Screws — Wood Deck Repair – FastenMaster HeadLok Screws

The HeadLok screws did a great job of pulling the joists together:

Wood Deck Repair - HeadLok Screws in Sister Joist — Wood Deck Repair – HeadLok Screws in Sister Joist

I installed the HeadLoks working below the deck on the ladder. The deck is about 14-1/2 feet high to the basement concrete patio:

Wood Deck Repair - Improper Deck Board Installed Parallel to Joists — Wood Deck Repair – Improper Deck Board Installed Parallel to Joists

Bolt the Splayed Rim Joists

The 2×10 rim joists (“beams”) have cupped and splayed apart at the bottom because the 16 penny smooth shank nails used by the home builder lack sufficient gripping ability. I clamped the bottom of the joists – which didn’t completely pull them together:

Wood Deck Repair - Pull Deck together with Come Along Cable Winch — Wood Deck Repair – Pull Deck together with Come Along Cable Winch

I drilled and installed a 1/2 inch x 4 inch long galvanized bolt with washers and nuts. The bolt and washers squeezed the 2×10’s together at the bottom to correct the splay:

Wood Deck Repair - Bolt in 2x10 Rim Joists — Wood Deck Repair – Bolt in 2×10 Rim Joists

Two socket wrenches made for quick work installing the 1/2 inch bolt:

Wood Deck Repair - Bolt in Double Joist — Wood Deck Repair – Bolt in Double Joist

Measure How Much the Wood Deck has Sagged

I’m almost ready to begin work on replacing the corner 6×6 deck post, but I need to know how much the deck needs to be raised to be level. Using a long aluminum straight edge and 5 feet long spirit level, I confirmed the original main deck on the left was level then placed blocks under the straight edge until it was level:

The deck has settled about 2-1/2 inches over an 8 feet span:

I’ll build a full height temporary support post out of 2×6’s and 2×4’s and jack up the deck in How to Replace a 6×6 Wood Deck Post.

Thanks for reading,

Bob Jackson