Drafts, dust and water at a sliding door come from worn pile weatherstrip in the panel edges and interlock, a missing bottom sweep, blocked weep holes in the sill, or a panel that has dropped and left a gap. We replace the seals, clear the sill drainage and reset the panel height so the door seals the way it did when it was new.
What you get
- Pile weatherstrip replaced in the panel edges, interlock and jamb where it has worn flat
- Bottom sweep and sill seal replaced so dust and water stop at the door
- Weep holes cleared so rain drains out of the sill instead of into the house
- Panel height reset when the gap is really a dropped roller
- Honest answer when a leak is the wall or the stucco, not the door
Where the air and water get in
A sliding door seals in four places. Pile weatherstrip, the fuzzy strip in a slot along the panel edges, seals the panel to the jamb and the head. The interlock, where the sliding panel and fixed panel overlap, carries its own pile. A sweep or sill seal closes the gap under the panel. And the sill has weep holes that drain rain back outside.
Pile wears flat, falls out or fills with dirt. Sweeps crack and tear. Weep holes clog with sand and leaves. When any of them goes, you get a draft on a windy night, a line of dust along the floor, or water on the tile after a storm.
Start on the symptom page if you are not sure which it is: gaps, drafts and water leaks.
Water at the sill during rain
San Diego gets its rain in a few heavy storms, and that is when the calls come. Water at the sill usually has one of three causes.
- Blocked weep holes. The sill is designed to collect water and drain it out through small slots on the outside. Sand, leaves and old caulk block them, the sill fills, and the water comes in over the inside edge. We clear and flush them.
- A worn sweep or sill seal. Wind-driven rain pushes under the panel. New sweep.
- A dropped panel. One corner sits low, so the seal is crushed on that side and open on the other. Rollers or an adjustment, not a seal.
Water that comes in above the sill, through the wall or at the top corners, is a flashing or stucco problem, not a door problem. We tell you that rather than sell you weatherstrip that will not fix it.
Need a draft or leak fixed this week?
Call or text with your address, how many doors and what the door is doing. You get a firm price before we come out.
Drafts, dust and noise
A draft at a sliding door is rarely the glass. It is the pile. Over the years the pile mats down, and the gap it filled is open. On coastal doors in Imperial Beach and Pacific Beach, the sand that blows in wears the pile faster and then scores the track.
We pull the panel, strip the old pile out of its slot, and press in new pile of the right height and width. There are several sizes, and the wrong one either does nothing or makes the door stiff, so we measure the old strip and the slot. The interlock gets the same treatment, and the sweep is replaced at the same time.
A door with fresh pile is quieter and keeps dust out. It is not a replacement for fixing a dropped panel, which is the next section.
When the leak is really a dropped panel
Many of the leak and draft calls we get are not seals at all. The sliding panel has dropped on worn rollers, so it sits tilted: tight at one bottom corner, open at the opposite top corner. New weatherstrip on a tilted panel seals the tight side and still leaves the open side.
The check takes a minute. Close the door and look at the gap along the top and the latch side. If it tapers, the door has dropped. Fix the height first, with an adjustment if the rollers are sound or new rollers if they are worn, then fit the seals to a panel that sits square.
We bring both to every leak call so the door is fixed in one visit either way.
What weatherstrip will and will not fix
- Will fix: drafts along the jamb, head and interlock; dust lines along the floor; wind noise; light water under the panel in heavy rain.
- Will not fix: a tilted panel, a racked frame, water coming through the wall or the stucco above the door, a cracked sill, or fog between the panes.
If the frame is racked, the gap changes along its length and no strip fills it evenly. Some of the 1960s and 1970s aluminum doors in Chula Vista and El Cajon have this from decades of settling. We can still cut the draft a lot with new pile and a sweep, but we say up front that it is an improvement, not a seal, and point you to the repair or replace guide.
Weatherstrip and leak repair across the county
Weatherstrip is priced per door on our pricing page and includes pile, sweep and clearing the weep holes. We combine it with rollers or a track cap on the same visit when the panel is already out, which is most of the time.
We carry pile in the common heights and widths for aluminum and vinyl doors, plus the sweeps and sill seals used on Milgard, JELD-WEN and old aluminum doors. Less common profiles on Andersen and Pella gliding doors are matched from a photo of the old strip.
Before the next storm, send us a photo of the sill and the gap and we will tell you which fix it needs.
Weatherstripping and Leak Repair: common questions
Why is water coming in under my sliding glass door when it rains?
Most often the weep holes in the sill are blocked with sand or leaves, so the sill fills and overflows inside. The other common causes are a worn bottom sweep and a panel that has dropped and opened a gap at one corner. We clear the weeps, replace the sweep and reset the panel height as needed.
What is the fuzzy strip on a sliding door called?
Pile weatherstrip. It is a dense fuzzy strip, often with a thin plastic fin down the middle, that slides into a slot along the panel edges and the interlock. It seals air and dust without stopping the door from moving. It wears flat over the years and is replaced by pulling the panel and pressing in new pile of the same size.
Can you stop drafts on an old aluminum sliding door?
Usually, yes. New pile in the panel edges and interlock, a new sweep and cleared weep holes cut most of the draft on a 1970s aluminum door. If the frame has racked so the gap tapers, weatherstrip improves it but cannot seal it completely, and we say so before we start.
Does weatherstripping fix a gap at the top of the door?
Only if the gap is even along the whole top. A gap that is wider at one end means that corner has dropped on its roller, and weatherstrip cannot fill a tapered gap. The fix is to raise the panel with the adjustment screw or replace the worn roller, then renew the seals.
How often should sliding door weatherstrip be replaced?
There is no fixed interval. Pile lasts many years inland and less near the beach, where sand wears it and salt stiffens it. Replace it when you can feel a draft with the door locked, see a line of dust along the floor, or see the pile matted flat or missing from the slot.
More answers on the FAQ page. Not sure what your door has? Send us a photo and we will tell you.
Where we do this
We cover all of San Diego County, usually within the week. Some of the places we work:
Related guides
- Repair or Replace Your Sliding Glass Door? An Honest Decision Guide – When a $250 to $400 repair brings a 40-year-old aluminum slider back, when the frame, glass or track means replacement, and typical costs for both.
- Signs Your Sliding Door Needs New Rollers (And Two-Minute Checks) – Symptoms of worn sliding door rollers in order of certainty, the two-minute checks you can do safely, and how to tell when the track is the real problem.
Ready to get the door gliding again?
Call or text for a straight answer and a price before we come out. Mon to Sat 7am to 6pm.