Water at your sliding door sill: where is it coming from?

The symptom

Water shows up in the sill track of the sliding door, or on the floor inside it, after rain. This guide helps you work out where the water is coming from, because that decides who should look at it. It does not ask you to take anything apart.

The short answer

Sort the water into three kinds.

• Pooling in the track that drains. Andersen says some pooling on the sill during heavy rain is normal and usually temporary.
• Water through the door. This points to the door: its weatherstrip, its drainage, the lock, the panel's height, or the panel itself.
• Water around the door. Water that comes in around the unit, not through it, as Andersen puts it, points to the installation and the sealant around it. A professional inspects that.

Normal pooling or a drainage problem

Andersen says that during heavy rain it is normal for some water to collect or pool on the sill, and that pooling in the sill is usually temporary. Some of its doors drain the sill through weep holes. It describes these as small openings on the exterior bottom edge of the sill that let water pass through the sill and drain away from the home. Other products, it says, use drainage methods that may not include visible weep holes.

If the water does not drain or the pooling persists, Andersen says the weep holes may be blocked by dirt, debris, or sealant.

JELD-WEN's vinyl door guide lists a clogged weep system first among the causes of water leaking through a patio door. Its remedy starts with cleaning the sill track with a vacuum or a damp cloth and pouring a small amount of water into the interior sill track. If the water does not drain out, it says to inspect the exterior and clear any blockage.

On some doors you cannot see the weep holes at all. Andersen says its 400 Series Frenchwood, 200 Series Perma-Shield, and 200 Series Narroline gliding doors have weep holes under the fixed panel, which are not visible once that panel is installed.

Water through the door

When the water comes through the door itself, the manufacturer documents we opened point to five things.

• Weatherstrip. Both JELD-WEN guides list damaged or missing weatherstrip as a cause of water leaking through the door. JELD-WEN says dust pads and weatherstrip placement are critical to water and air infiltration control. Andersen says to check the weatherstrip for gaps, damage, or permanent compression, and recommends replacing any weatherstrip that has gaps, signs of damage, or typical wear and tear.
• Drainage. JELD-WEN's vinyl door guide lists a clogged weep system, covered above.
• The lock. Andersen says a partially closed or unlocked patio door can compromise its ability to seal against the weather.
• Panel height. The rollers under the sliding panel set how high it rides; the roller repair page covers them. JELD-WEN warns that adjusting the door too high may allow water and air leakage. Andersen points to adjustment when a door is difficult to operate, appears misaligned, or does not seal properly.
• The panel. JELD-WEN's wood door guide lists a panel that is damaged or loose at its joints.

Water around the door

Andersen says water infiltration can happen for several reasons, some related to the door itself and others to its surroundings. It says a visual inspection of the installation area can help find the source, especially when water comes in around the unit, not through it. It says sealant should be applied at the ends of the sill and side jambs to help prevent water from entering around the unit.

JELD-WEN's guides say their instructions do not cover water-tightness or flashing. Both say a water-tight inspection requires removal of the exterior siding around the patio door. Both end the note the same way: "Seek professional assistance regarding this issue."

Andersen also lists damage from severe weather as a cause of water infiltration.

What you can check safely

Each check is done with the panel in place.

1. Watch where the water appears. After the next rain, note whether it is in the track, on the floor at the meeting point of the two panels, at a corner of the frame, or under the sill. Note whether it comes with every rain or only in heavy rain.
2. Close and lock the door. Because Andersen says an unlocked or partly closed door can compromise its seal, keep the door closed and locked in rain.
3. Clean the sill track. Andersen's method is a soft-bristle brush with warm, mild soapy water, a rinse with clean water, and letting the track dry before the door is closed. JELD-WEN cleans it with a vacuum or a damp cloth.
4. Test the drainage. JELD-WEN's test is to pour a small amount of water into the interior sill track and see whether it drains out. If it does not, its next step is to inspect the exterior and clear any blockage. Follow your own door's instructions for that.
5. Look at the weatherstrip. Check it for gaps, damage, or flattening along the bottom of the sliding panel, at the meeting edge, and around the frame.
6. Look at the outside of the frame. From outside, look at the ends of the sill and the side jambs, where Andersen says sealant should be. Note any gap or crack. Do not remove siding or trim.

Leave the roller adjustment screws alone. JELD-WEN's guides warn that a panel set too high lets in water and air, and they show that the direction of turn differs between door lines.

When to ask for a repair

Ask for help in any of these cases:

• water still comes in with the track clean and the door locked;
• the test water does not drain out of the sill track;
• the weatherstrip is damaged, flattened, or missing;
• water comes in around the door, not through it;
• the panel looks damaged or loose at its joints;
• the door was damaged in a storm.

Water around the door calls for someone who inspects the installation and flashing. JELD-WEN says that inspection requires removal of the exterior siding. Water through the door is the kind a sliding door repair covers.

What a technician does

A technician starts from what you saw: where the water appears and when. The sill track and its drainage are cleaned and checked. The weatherstrip is checked and replaced where it is worn or missing. The panel's height and lock are set so the panel seals. Where the water comes in around the frame, the technician says so, and the installation and flashing are a separate job.

Where to go next

• The track repair page covers a damaged or worn sill track.
• The alignment page covers a panel that sits out of adjustment.
• If you also feel air at a bottom corner, read drafts at the bottom corner.
• The repair-or-replace guide helps when the panel or frame itself is damaged.

To ask about a repair in Plano, Allen, McKinney, or Frisco, describe where the water appears and when on the contact page. The photo guide lists what to photograph first. The operator reviews every inquiry and replies with the next step. Sending the form is not a booking.