Partial clog after remodel

Quick Answer:

Construction dust, plaster, grout and tile debris commonly settle in traps and the short tail pieces under new fixtures, causing slow or partial clogs that look worse than they are. Start by removing strainers and cleaning visible debris from traps and fixture tails, use a shop‑vac on accessible traps, and flush the nearest cleanout with an outdoor hose while watching the flow. If multiple fixtures are affected, snake the branch first and then the main from the cleanout. If debris still sits inside the line, ask for a camera inspection and professional cleaning.

Why This Happens

Renovations kick up a lot of fine dust and larger grit. Drywall dust, plaster, thinset, grout beads and mortar can land in sinks, tubs and floor drains. Many of those particles stick together or bind with water and form a gummy, sand‑like mass that lodges where the pipe changes direction — most often in the trap or the short “tail” piece connected to the fixture. That creates a partial clog that slows draining but usually doesn’t mean the main sewer line is damaged.

Step-by-Step What to Do

Inspect and remove strainers

• Remove pop-up covers, sink strainers and tub/shower screens.
• Look into the drain and the trap for visible plaster, grout or grit and pull out what you can with gloved fingers or pliers.
• Clean the fixture tail pieces (the short pipe right under the strainer) — debris often collects there before reaching the trap.

Use a shop‑vac on accessible traps

• Set a wet/dry shop‑vac to the proper mode and vacuum loose dust and plaster from the trap and the open tail piece.
• If the trap is removable and you’re comfortable doing that, take it off, clean it thoroughly, then reinstall a new washer or seal if needed.

Flush the line from the nearest cleanout

• Locate the outdoor cleanout (usually near the foundation or along a yard-facing sewer run) and carefully remove the cap — sewer gas can be present, so open slowly.
• Run a garden hose into the cleanout and use steady, moderate flow to push sediment toward the street while someone watches fixtures inside for increased flow or back-up.
• Do not use improvised high-pressure water from random equipment; use a garden hose at normal pressure and watch for returns at fixtures.

Snake the branch, then the main

• Start snaking from the affected fixture or its access point to clear the branch line first. A hand auger (10–25 ft) is often enough for trap and branch clogs.
• If several fixtures are slow or out, snake from the cleanout into the main sewer. Progress slowly and avoid forcing the auger if you feel a hard obstruction.

If debris persists

• Request a camera inspection to locate the debris and confirm whether it’s in the branch or the main line.
• A professional cleaning (often hydro‑jetting) will remove compacted plaster or grout that homeowners’ tools cannot.

Tools and supplies to have on hand: gloves, safety glasses, dust mask, screwdriver, bucket, flashlight, shop‑vac, hand auger, garden hose and a small mirror if needed.

If the remodel included a plumbing repair, see Partial clog after plumbing repair. If a new filter or softener was added, see Partial clog after filter install.

What Not to Do

• Don’t ignore drywall dust and grout sitting in traps — leaving it will often make the clog worse.
• Don’t try to push large chunks of debris down the line with high‑pressure water from random hoses or equipment; that can move debris deeper and make removal harder.
• Don’t delay calling a pro when construction debris can’t be removed from the trap or when several fixtures back up despite cleaning.

When to Call a Professional

• Multiple fixtures are slow or backing up after you’ve cleaned strainers and traps.
• You can’t remove compacted plaster or grout with a shop‑vac and a hand auger.
• You want confirmation of the problem location — a camera inspection identifies whether the blockage is in the branch or the main line.
• Professional cleaning (hydro‑jetting or powered augers) is needed to remove hardened sediment without damaging pipes.

Safety Notes

• Wear gloves, eye protection and a dust mask when disturbing drywall dust, plaster or grout.
• Open outdoor cleanouts slowly to avoid exposure to sewer gas; keep children and pets away while you work.
• Use a shop‑vac according to the manufacturer’s instructions; don’t use a vacuum not rated for wet use on wet debris.
• Avoid chemical drain cleaners for plaster or grout — they won’t remove solids and can create hazardous conditions if mixed with other substances.

Common Homeowner Questions

• Can construction debris damage the main sewer line? — Unlikely; most debris lodges in traps or branch lines, but get a camera if multiple fixtures back up.
• Is a shop‑vac OK for plaster and grout? — Yes for loose debris in accessible traps, using the correct wet/dry setting and proper PPE.
• Will drain chemicals clear plaster or grout? — No; chemicals won’t dissolve these materials and can make cleanup harder or unsafe.

More in this topic

For more related fixes and similar symptoms, see Main Line Partial Clogs.