Most posts soft at the waterline
Once a majority of the grid has failed in the same band, you are building a new boathouse around old timber and paying twice.
Boathouse Repair · Texas & Western Louisiana
A boathouse fails one component at a time.
Roof, framing, posts, hardware, deck and lift structure run on six separate clocks. Repair is working out which one has run down — and saying so when the answer is that the substructure is finished.
First, The Word Itself
A boathouse is not a houseboat.
The two get searched with the same words and repaired in entirely different trades.
A boathouse is a covered slip built over water on driven posts or piles — a framed deck, a roof, usually a lift, and it does not move. A houseboat is a vessel with a fiberglass hull. Most of what is written about boathouse roof repair is really about resealing fiberglass.
This page is about the structure. Shoretech has been on this water for more than 40 years — over 250 boathouses and 850-plus projects — and repair work is regularly on slips somebody else built. If the trouble is under the deck, see dock and pier repair; if the shoreline wall has moved, seawall and bulkhead repair.
Why Owners Misdiagnose It
You can only see two of the six layers.
Roof and decking are visible from the lawn. Framing, hardware, the posts at the waterline and the lift support are not — and those four decide whether a boathouse has five more years or thirty. New material over a failing layer silences the symptom and lets the problem carry on.
So the calls come in about the roof and the boards. Nearly every time, the leaking panel is reporting on the purlin under it.
Roof Panels & The Purlins Under Them
Most boathouse roofs fail at the fasteners, not the metal.
A metal roof over open water expands, contracts and gets lifted at every blow — and the panel usually outlives the screws holding it down.
Fastener back-out. Roofing screws seal on a rubber washer. Sun hardens it, thermal movement works the screw loose, and each one that lifts becomes a hole pointed at the timber below. Stand under the roof at midday and look up: pinholes of daylight along a fastener line are the diagnosis, and so are rust rings around the screw heads from above.
Follow the water down. A run of framing darkened while everything around it is dry is the actual damage, and it started long before the roof looked wrong. Check the shallow runs first: where a roof dies into a wall or steps down to a lower deck, leaves hold water on the panel for days.
Repair or re-sheet. Sound panel with backed-out fasteners is a repair: larger-diameter screws into fresh timber, seams and flashing renewed. Perforated panel, or purlins that take a screwdriver at the fastener line, is a re-sheet — and re-sheeting over rotted purlins buys the same job again.
Hardware
The cheapest parts of a boathouse, and the ones that end it.
Rust streaks are a diagnosis, not a stain. A dark bleed under a bolt head means the fastener is corroding inside the timber, where nobody can measure what is left. We pull a sample rather than assume.
A crushed washer means soft wood. If the washer has pulled into the timber, the bolt is clamping nothing, and that connection needs new wood rather than a new nut. An oval bolt hole says the frame has been moving under load and the bracing has gone slack.
Mixed metals cause their own trouble. A coated screw dropped into a stainless assembly, or a plain bolt substituted during an earlier repair, creates corrosion where there was none. Renewal goes back in hot-dip galvanized or stainless, consistent within the joint — Built to Last sets out why.
Posts in the Splash Zone
A post dies in a band a few inches tall.
Not at the mud line and not at the top, but in the strip that is alternately wet and dry, where fresh water and air together take timber apart.
1
Probe it, do not look at it
Push a long screwdriver into the waterline band and lean on it. Sound timber pushes back; a failing post takes the point under hand pressure. Add the visual tells — an hourglass narrowing at the water, rust bleeding from a bolt hole, a post out of line. A post can look perfect from the deck and have lost most of its section at the surface.
2
Boathouse posts carry more than dock posts
They take roof uplift in tension, the dead load of the structure, and often a boat in the air on a lift. A soft post under a covered slip is more urgent than the same post under an open walkway, and we count how many are affected before talking about scope.
3
Sistering, and what a wrap does not do
Where the loss is local, a new pile is driven hard alongside and the framing transferred onto it with new through-bolted hardware. A wrap keeps water off timber that still has section; it puts nothing back into a post that has lost it. Splicing works only above the waterline band — rarely where these posts fail.
Racked & Shifted Structure
When a boathouse moves, it tells you in three places.
High water, a hard blow, or a boat that got away in the night can push a structure out of position. It rarely comes back on its own.
The doors. A slider that used to run and now binds is the first thing most owners notice — the frame reporting that it is no longer square.
The diagonals. Measure corner to corner across the slip opening, both ways. Equal means square. An inch or two of difference across a big opening is a racked structure, and it keeps going the same direction until the bracing is restored.
The ridge. Sight the roof ridge against the far shore. A bow, a dip over one bay, or a ridge no longer parallel with the deck says the frame under it moved, not the roof.
After high water, photograph before moving anything: debris lodged against a post is still applying load.
Decking & Lift Support
Two more layers, and only one of them is cheap.
Re-decking is the best value in boathouse repair when the frame is genuinely sound. The lift structure is the opposite: small, hidden, heavily loaded.
Decking over sound framing. Every board comes up, the stringers and beams get probed rather than glanced at, anything soft is replaced, and only then does new surface go down. A springy deck was telling you about the frame; new boards silence the message without changing the meaning. If the surface is composite, joist spacing gets measured first — those boards are rated by the span they cross.
Lift support structure. The header, beams, brackets and through-bolts a hoist hangs from carry a load nothing else sees, and they see it repeatedly. Look for a cradle that no longer sits level, a beam sagging under load, brackets weeping rust, or bolts that have worked their holes oval. We repair and reinforce that structure; cables, motors and controls go to a lift technician.
Repair, or Rebuild
What says the substructure is done.
Everything above the posts can be renewed piece by piece. The posts are the one layer that cannot.
The frame will not come back square
A structure that can only be pulled straight by loading connections already softened has spent its bracing.
Repeat repairs in the same bays
If a repair only buys a season, the diagnosis was wrong. Twice in one place means putting the money into structure.
Rot has reached the load path
Soft timber at the beam bearings and post tops means the members a repair would attach to are the ones that have gone.
We say so early when a structure is past repair, because mobilizing a barge and a pile-driving rig does not scale down the way material does. If that is where you are, a new boathouse is the next conversation, not a longer list of patches.
Where We Do This Work
Forty years on the same water.
Based in Trinity — more than 40 years, over 250 boathouses and 850-plus projects.
Lakes with completed Shoretech work
Service area
- Texas and western Louisiana waterfronts
- Private ponds and small lakes
- Subdivision, association and commercial shoreline
- Dave travels as far as the work requires
Questions We Hear
Boathouse repair FAQ.
Is it a boathouse or a houseboat, and why does the difference matter?
A boathouse is a covered slip built over water on driven posts or piles. It does not move. A houseboat is a vessel with a fiberglass hull. Search for boathouse roof repair and most of what comes back was written about houseboats, which is why covered-slip owners find so little that helps.
How do I know if my boathouse roof needs repair or full replacement?
Two questions decide it. Has the panel itself failed — coating gone, rust through, edges opened up — or is it only the fasteners that let go? And is the timber sound where the screws land? Backed-out fasteners in good panel over good purlins is a repair.
Can rotted boathouse posts be spliced or wrapped instead of replaced?
A wrap keeps water off timber that still has section; it puts no strength back into a post that has already lost it. Splicing works above the waterline band, with sound timber below to land on, which is not where these posts fail. The structural repair is a new pile driven alongside.
My boathouse leans or racks in the wind. Is that the frame or the posts?
Measure before you guess. If the posts are plumb and the structure above them has gone out of square, it is bracing and connections. If the posts lean and the frame on top is still square, the trouble is below the deck.
Can you repair a boathouse you did not build?
Yes. A repair visit is a diagnosis before it is a quote: posts probed at the waterline, connections checked rather than assumed, the frame measured for square, and the roof read from underneath.
Do you repair boat lifts?
We repair and reinforce the structure a lift hangs from — beams, headers, brackets and through-bolts — and mechanicals go to a lift technician. Our guarantee typically runs 2 to 5 years on the large Texas and Louisiana lakes and up to 10 years on private ponds and small lakes, with the terms set out in your agreement for the job.
Read Next
Related pages.
Start With What You Can See
Send photographs, then have Dave walk it.
The underside of the roof at midday, any post at the waterline, and the bolted connections where braces meet posts. Tell Dave what changed, and when.