Willow Glen is a San Jose neighborhood of older houses and bungalows, in ZIP 95125, about 5 km south-west of downtown, and many of its roofs are original 1920s to 1950s stock. This guide explains how such a roof is kept sound over time, what its faults usually are and the checks that keep it in order without a full re-roof every few years.
Key takeaways
- Many roofs in Willow Glen are original 1920s to 1950s stock, and their decks and flashings are the parts to read first.
- The rafter ends and the eave fascia are the parts most often rotted on these roofs, because the water runs off the covering into them.
- Original flashing is often lead, galvanised steel or a bituminous strip, and it is checked for lift and for brittle metal.
- A check each autumn from the ground and the attic finds the faults while they are still small.
- A recover over a failed deck hides the failure; the deck is checked before any new covering goes on.
What is an original roof of this age usually made of?
An original roof of the period typically has a plank or early panel deck, a covering of wood shingle, shake or early asphalt, and flashings of lead, galvanised steel or bitumen. Each has its own life and its own faults.
The deck of the period is often plank sheathing, with boards that have shrunk and gapped over the decades. The nails that hold them have worked loose in many places, and the technician checks each one.
Covering of that age may be wood or early asphalt, and the layers beneath it show the history of the roof. Each repair is visible in the attic as a patch of different wood or nailing.
Why are the rafter ends and the eave the usual trouble?
Water runs off the covering into the eave, and the rafter ends and the fascia behind the gutter take the run-off. Over decades the wood softens, and the gutter loses its fixing.
A rafter end that is soft is found by probing with an awl or a screwdriver. Sound wood resists, and rotted wood gives. The affected length is cut back to sound grain and a new piece is fixed alongside.
The fascia behind the gutter is checked in the same visit. A gutter that overflows at one corner softens the board beneath, and the board is replaced before the gutter is re-hung.
How are the old flashings read?
The flashings of an original roof are read for lift, brittleness and rust. Where they are sound, they can be lapped under a new covering. Where they have failed, a modern metal is fitted in their place.
Lead flashing that has become brittle cracks when it is bent, and a crack lets water run behind it. The technician checks each piece by lifting its edge gently, and replaces any that tear or split.
Galvanised flashing is checked for rust at the cut edges and the fixings. Bitumen strips are checked for splitting, and a strip that has dried out is replaced in full.
| Part | Usual fault | Usual fix |
|---|---|---|
| Deck | Loose nails, gapped plank, soft boards | Reset nails, replace soft boards |
| Rafter ends | Rot at the eave from run-off | Cut back to sound grain and sister a new piece |
| Fascia and gutter | Soft board behind an overflow | Replace the board, re-hang the gutter |
| Flashings | Brittle lead, rusted steel, dried bitumen | Replace with a metal suited to the exposure |
| Vents and chimney | Cracked mortar, lifted cap, split boot | Repoint, re-cap, replace the boot |
Why is a re-cover over a failed deck a false economy?
A new covering over a failed deck hides the failure and fixes the new covering to boards that cannot hold it. The fault then shows in the first storm as a lifted edge or a leak that is hard to trace.
A covering nailed into a soft board pulls out under wind, and the nails fail one by one. The owner then has a new roof that leaks where the old one was failing, and the new covering must be removed before the damage can be repaired.
The strip to the deck is the more honest option when the deck is in doubt. It costs more time, and the scope says why.
What is the autumn routine for an original roof?
An autumn routine checks the covering from the ground, the gutter and the outlets, the flashings at the vents and the chimney, and the attic beneath. The list is kept with the file and compared season by season.
From the ground, the covering, the gutters and the flashings can be seen with binoculars or a camera. From the attic, the boards, the rafter ends and any stain are read from the hatch.
The photographs from each season go into the file, so a change is seen rather than remembered. A check that finds the same fault each year points to a cause that has not been corrected.
An original roof also needs its ridge checked after a windy season, since the ridge takes the wind across its length and an old mortar bed can crack and lift a piece. A loose ridge piece is re-set rather than sealed, and the owner notes any gap or change in the line of the ridge for the next visit.
When does an original roof need more than care?
An original roof needs more than care when the deck has failed across several slopes, when the rafter ends are rotted in many places or when the flashings have failed in most of their positions. At that point a strip and re-roof is the sounder choice.
The technician records the extent of each failure on the scope. A few soft boards are replaced in a repair; a widespread failure is a reason to strip, and the owner is told why.
The decision is made on the record. The owner has the photographs, the counts and the reasons, and can compare them with any other quote on the same lines.
How are the gable ends and the chimney read on an original house?
The gable ends and the chimney of an original house are finished in brick, plaster or wood, and their flashings were fitted before current practice. The technician checks the mortar, the flashing and the junction with the wall, since each can carry water into the framing.
A repointed chimney and a new flashing are often sound for many years. The owner is told the age of the flashing and the condition of the mortar on the scope, so the next check knows what to look for.
A gable end with a crack in its plaster or wood is checked from the attic for wet framing behind it. The crack is repaired and the junction with the roof is re-flashed in the same visit.
What does the attic of an original house show?
The attic of an original house shows the history of the roof: the patches, the old nailing, the vents and the stains of past leaks. It is the most informative part of the check, and it is read from the hatch with a torch.
Each patch in the attic is a repair that somebody made, and the technician reads it for its date and its quality. A patch with a matching nail pattern and a sound overlap is a good repair; a patch laid over rot is a sign the source was never found.
The vents are checked for blockage. An original attic may have few vents, and a blocked intake makes the heat and moisture problem worse. The technician clears the intake and notes where a vent could be added.
How is a repair planned around the neighbors?
Original houses in Willow Glen often sit close to their neighbors, and the work is planned with their boundaries in mind. The crew keeps its materials on the owner's side, and the neighbors are told the days when the work is overhead.
A ladder placed on a narrow side yard can block a gate or a path. The crew agrees the position with the owner and checks that the route is clear before the day begins.
The neighbors are told the working days where their boundary is close to the roof. A short notice with the phone number for questions avoids complaints and keeps the work moving.
How do owners of original roofs keep the records?
Owners of original roofs keep a file with the dated photographs, the scopes, the counts of soft boards and the notes of each repair. The file is the only record of the roof's history that will survive the next owner.
The file holds one page for each visit, with the date, the parts checked and the repairs made. A photograph taken from the same spot each time shows the change, and the notes say which fault was seen and which was fixed.
A file that is kept carefully is worth more to a buyer or an insurer than any statement about the roof's age. It shows what has been done and what remains to be watched.
What does a roof in this neighborhood ask of the owner between visits?
Between visits the owner walks the house from the ground, notes any change in the covering or the gutter, and watches the ceilings after rain for a new stain. Each observation is dated and kept in the file.
A walk around the house once a season is enough for most original roofs. The owner looks for a lifted edge, a dip in a gutter, a bent flashing and any growth of moss that holds the wet against the covering.
After rain, the owner checks the ceilings in the rooms under the roof for new stains. A stain that has appeared since the last check is reported with its position, so the trace can start in the right room.
Frequently asked questions
Can an original roof in Willow Glen be walked on?
Only on the boards and at the ridge, and only by a technician. The deck of the period can be soft in places and will not carry a person's weight everywhere.
How long should an original roof last with care?
It depends on the material, the deck and the exposure. The technician reads the roof and says what it shows, rather than promising a number of years.
Will the new covering match the look of an old house?
A close match is often available. The technician tells you where a new shade will show before the work starts.
Sources
This guide is general information for Santa Clara County homeowners, not a substitute for an on-site inspection. Prices are estimates. See our disclaimer.