A box of screws marked "outdoor" sounds reassuring. It still may not contain the fastener specified for that joist hanger.
Deck hardware has two jobs to get right: carrying the load and surviving the environment. One does not cancel the other.
Start with the connector model
Ask for the manufacturer's specified nail or screw, including diameter, length, and installation pattern. We keep the connector schedule with the hardware boxes, because two similar-looking screws can end up side by side when crews are doing framing and decking together. On a repair, a box of leftover deck screws was set aside before the hanger work began. Being handy in the toolbox doesn't make a fastener suitable for the connection.
Simpson Strong-Tie's connector guidance explains why connectors and fasteners must work together. If a substitution is proposed, ask for the applicable manufacturer approval rather than a general claim that the alternative is stronger.
Deck screws, connector screws and bolts are different purchases
| Connection | What identifies the right fastener |
|---|---|
| Deck board to joist | The decking instructions and fastener approval for that wood and exposure. |
| Joist hanger or framing connector | The exact connector model's approved nail or screw schedule, including diameter, length, quantity and hole pattern. |
| Ledger, beam, post or guard connection | The approved structural detail and the named hardware system. A general-purpose deck screw is not evidence of an approved connection. |
A screw fitting through the hole proves only that it fits. Simpson's connector guidance also says not to combine nails and screws within one connector unless its load table permits the combination. Use the current instructions for the specific model, not the picture on a similar box.
Then match the exposure
The manufacturer's treated-wood FAQ discusses how treatment chemistry and conditions affect corrosion. The timber treatment and its intended exposure need to be known when selecting hardware.
A damp, poorly ventilated corner under a low deck is a different setting from a sheltered interior connection. Nearby salts or persistent water can make the selection more demanding. "Pressure treated" describes a broad category, not every relevant property of the wood.
What do galvanized, ZMAX and stainless actually tell you?
Simpson's treated-wood FAQ distinguishes the coating processes and identifies ZMAX as a G185 coating on its connectors. Ordinary electrogalvanizing is not the same specification as hot-dip galvanizing. A bright silver finish cannot tell you which you have.
| Label you see | Check before buying |
|---|---|
| Galvanized | Which coating standard and thickness? Is that exact product approved for the treatment and exposure? |
| ZMAX or another named connector coating | Which compatible fastener coating and connector installation schedule does its manufacturer require? |
| Stainless steel | Which grade and matching connector system? Stainless screws alone do not make a mixed assembly suitable. |
| Coated exterior screw | Is it approved for this lumber AND the structural connector, or only for a different fastening job? |
Keep the metal system compatible
Do not assume mixing metals creates an upgrade. Simpson recommends compatible connector and fastener corrosion systems, such as stainless fasteners with stainless connectors. Follow the actual product documentation for the assembly. Keep a photo of the lumber treatment tag and the hardware labels before the packaging disappears. If a supplied part changes, check the combination again rather than treating a shinier finish as automatic approval.
| Ask to see | Why it helps |
|---|---|
| Connector identification | Lets you find its installation requirements. |
| Fastener specification | Makes substitutions visible before installation. |
| Wood treatment information | Supports the corrosion-resistance selection. |
| Photos before concealment | Records connections that fascia may later hide. |
Rust is a question, not a cosmetic diagnosis
Surface staining, substantial metal loss, and a connection pulling apart are not equivalent conditions. A homeowner photograph cannot establish remaining capacity. Have deterioration assessed, especially where supports or guards are involved.
Painting a rusty bracket may improve the photograph. It does not explain why the bracket corroded or whether the fastening is adequate. Use the deck safety checklist to inspect the wider structure. If the problem is at the house, read how the ledger and flashing work together; if a guard moves, start with the loose rail-post guide.