The Old Tradesman

The tips library

Sillcocks done right

A frost-free sillcock only works if it goes in the way the maker drew it. Get the pitch, the length and the inlet end right and, with the hose off, it drains dry every time you shut it; miss one and it splits inside the wall where you can't see it.

Tip 1

Pitch the barrel down toward the outside.

The number

Set it so the spout end sits lower, about 5 degrees. Inside, the word TOP on the inlet faces up.

Frost-free sillcock pitched down toward the outsideSection through a house wall with a frost-free sillcock. The valve seat is at the inlet end inside the heated house, with TOP on the inlet connector facing up. The barrel slopes down about five degrees to the spout outside, set with a beveled wedge behind the flange, so the barrel drains out the spout when it is shut.FROST-FREE SILLCOCK, PITCHEDINSIDE (heated)OUTSIDETOPlevelspout endlower, about5 degreesSeat shuts offhere, in the heatTOP on the inletfaces upBeveledwedgeThe barrel drains out the spoutwhen you shut it. Level, it holds water.

Why. A frost-free shuts off at the inlet end, inside the heat. The barrel drains out the spout after you close it. Water left in it freezes.

The tell. Dead level or rolled over, it holds water. Woodford marks its tube: alignment mark pointed down.

A.Y. McDonald puts the angle at about five degrees and packs a gray beveled wedge in the box to go between the wall and the flange to set it. Woodford's sheet says nozzle pointing down and a slight downward pitch for proper drainage. And take the hose off in freezing weather: A.Y. McDonald says with a hose on, the sillcock can't drain and trapped water can freeze and damage it. Fine Homebuilding traces most burst frost-free faucets to a hose left on.

When to stop. Hole drilled so it cannot pitch? It gets redrilled. Through block or brick, that is a plumber with the right drill.

Sources

Tip 2

Caulk the flange, but don't insulate over the inlet.

The number

Outside, caulk the flange top and sides, bottom left open. Inside, keep insulation off the inlet connection.

Caulk the sillcock flange outside, keep insulation off the inlet insideSection through a house wall with a frost-free sillcock. Outside, caulk seals the top and sides of the flange, with the bottom edge left open to drain. Inside, insulation in the joist bay stops short so the inlet connection and valve seat sit open to the house heat.CAULK OUTSIDE, HEAT INSIDEINSIDE (heated)OUTSIDETOPHouse heatkeeps theinlet warmInsulation stopsshort of the inletCaulk topand sidesNo insulation over the inletconnection. Seal the hole outside.

Why. The seat stays above freezing on house heat. Bury the inlet in insulation and you cut it off from that heat.

The tell. Rim joist stuffed with insulation right around the sillcock inlet. Pull it back off the inlet end.

A.Y. McDonald prints it with an exclamation point: do not insulate over the inlet connection. The sheet doesn't say why; my read is the one above, because SupplyHouse says the shutoff seat has to sit inside heated space. The caulk is the other half. Richard Trethewey caulks behind the flange on This Old House to keep the heat inside the building, not just to keep the rain out. SupplyHouse goes one better: seal the top and sides and leave the bottom edge open to drain; over-sealing traps water.

When to stop. Inlet sits in an unheated crawl space or garage? Moving the supply to the heat is a plumber.

Sources

Tip 3

An anti-siphon sillcock is not a manifold. 12 hours, tops.

The number

Woodford's anti-siphon wall faucet sheet: no more than 12 hours of continuous water pressure. Shut the sillcock when you're done, not just the nozzle.

Why. The anti-siphon part is a vacuum breaker. Contractor Magazine says one held under pressure can stick closed and not open to air when it is needed.

The tell. A shutoff nozzle or a hose timer on the spout with the sillcock left open all day. That holds the breaker under pressure.

Contractor Magazine lays out the 12 hour limit for atmospheric vacuum breakers, and says a hose connection vacuum breaker is one of those. Under continuous pressure the valve can stick from mineral deposits, and anything downstream that holds pressure, a shutoff or a solenoid valve, keeps it there. The pressure type vacuum breaker was built to get around that limit, and that's the kind of question your plumber and inspector settle for a sprinkler line.

When to stop. A line that has to stay pressurized, like a sprinkler feed, needs its own backflow device per local code. That is a plumber.

Sources

Tip 4

Buy it long enough to put the seat inside the heat.

The number

Length at least 2 inches more than the wall is thick, on the inlet side. Anywhere it freezes, A.Y. McDonald recommends a length of 6 inches or more.

Sizing a frost-free sillcock: at least two inches longer than the wallSection through a house wall with a frost-free sillcock. The length, measured from the flange to the inlet end, runs through the wall thickness and at least two more inches into the heated space so the valve seat sits in the heat. Anywhere it freezes, A.Y. McDonald recommends six inches or more.HOW LONG A FROST-FREEINSIDE (heated)OUTSIDEwall2 in or morelength: flange to inlet endSeat at the inlet end, past theinside of the wall, in heated space.Anywhere it freezes, the makerrecommends 6 inches or more.

Why. The valve closes at the inlet end. If that end sits in the wall cavity or the rim joist instead of heated space, the water at the seat can still freeze.

The tell. Most makers measure from the mounting flange to the inlet end. Measure the old one that way, or measure the wall at the hole and add the margin. An inlet that ends inside the wall is the mistake.

SupplyHouse says it flat: the shutoff seat must sit inside heated space. A short sillcock in a thick wall puts the seat right where the cold gets in.

When to stop. If the new length means rerouting the supply through a finished ceiling or a packed joist bay, that is a plumber.

Sources

Tip 5

Sweating a frost-free: open it, pull the stem, aim the flame away.

The trick

Open it all the way and pull the stem before the torch comes out. Point the flame away from the valve, do not overheat it, and put the stem back after it cools.

Why. The rubber seat lives at the inlet end, the end you're soldering. Woodford says too much heat can damage the seat rubber, a stainless seat and the factory solder joint.

The tell. A brand new sillcock that never quite shuts off. The seat got cooked.

A.Y. McDonald says open it fully and remove the stem before applying heat, direct the flame away, and don't overheat. This Old House pulls the stem so the rubber seat doesn't melt. SupplyHouse says use a heat shield and let it cool before it sees pressure.

When to stop. Torch work in a tight rim joist against wood: if you can't shield it, that's a plumber.

Sources

Tip 6

Screw the flange to something solid.

The trick

Two screws through the flange into solid backing. Brick or block gets masonry hardware.

Why. Every turn of that handle twists something. Anchored, the flange takes it. Loose, the soldered joint inside the wall takes it.

The tell. The whole faucet turns a little when you turn the handle. It is not anchored.

SupplyHouse: solid anchoring keeps handle torque from stressing the joint inside the wall. A.Y. McDonald calls for two screws and masonry hardware on brick or cement, and Woodford's adjustable flange matches the slope of the siding.

When to stop. Nothing solid behind the siding to screw into? Adding blocking means opening the wall.

Sources

The Old Tradesman is a cartoon character. Every tip on this page stands on the sources listed under it. He is the voice. They are the authority. The drawings are diagrams, not photographs.

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