All guides
All 22 guides
Every guide on the site, grouped by section. No dropdowns: this page is the index.
The Roof
- A Roof Over a Bridge Is a Maintenance DecisionUntreated timber lasts a handful of years wet and many decades dry. The roof and siding exist to keep water off the trusses; everything picturesque about them is a side effect of that arithmetic.
- Why the Siding Stops ShortOpen strips under the eaves and above the deck let air move and light in. What that gap is for.
- The PortalThe opening at each end sets the clearance and takes the damage. Why it is the most-repaired part of the structure.
- Fire and FloodThe two things that actually destroy them, and why a covered bridge is more likely to leave in a river than to fall down.
Trusses
- The Truss Is the BridgeThe roof gets the attention; the truss does the work. How a triangulated frame turns bending into tension and compression, and why that lets timber span further than a beam.
- The Burr ArchAn arch superimposed on a truss so the two share the load. Common, effective, and argued about ever since.
- The Town LatticeA criss-cross of planks pinned with treenails, patented so it could be built by anyone with sawn lumber and no fine joinery.
- Howe and PrattWhich members take tension and which take compression — the distinction that decides where iron replaces wood.
- Smith and ChildsLater proprietary types sold as kits with instructions. What standardisation did to bridge building.
- The Longest Covered Span in the CountrySmolen–Gulf, its length, and what building at that scale demands of a timber structure.
Load
- Where the Force GoesFollowing a load from a wheel through the deck, into the floor beams, out through the truss and down to the abutment. The path that explains every member you can see.
- A Loaded Wagon Against a Modern TruckThese were designed for a different traffic. What posting a weight limit is actually doing.
- Treenails and Iron RodsWooden pins that swell to grip, and the iron that later took the tension. Two eras of fastening in one structure.
- What Fails FirstBearing points, the ends of chords, and anywhere water sits. Decay follows moisture, not age.
Building
- Raising a SpanFalsework in the creek, assembly on the bank, and getting a truss into position without a crane. How it was actually done.
- A Bridge Built This CenturyThe county kept building them — with glue-laminated timber and modern engineering. What that changes and what it deliberately keeps.
- Glue-Laminated TimberEngineered wood that behaves predictably where a sawn beam does not. Why it made new covered spans viable.
- The County That Kept GoingWhy this concentration exists here: geology, creeks, county policy and a deliberate decision not to stop.
Keeping Them
- Repair or ReplaceSistering a chord, splicing a member, jacking a span. When a repair preserves a bridge and when it quietly produces a new one.
- How Much Can Be ReplacedIf every timber is renewed, is it the same bridge? The question preservation bodies actually have to answer.
- Bypassed, and Therefore SavedMost survivors were spared by a new road alongside. Redundancy as a preservation strategy nobody planned.
- What an Inspection Looks ForMoisture, section loss and connections. The unglamorous routine that keeps a timber structure standing.