What actually causes moth damage
The culprit is almost always Tineola bisselliella, the common clothes moth. The adults do not feed on wool — they only mate and lay eggs. It is the larval stage, hatched into the fibre itself, that does the damage. Larvae eat the keratin protein in wool and silk, building small tube-shaped cases out of silk and consumed fibre as they move.
Larvae prefer dark, undisturbed, slightly humid areas. Under furniture. Inside closets. Against walls where a rug meets the baseboard. In storage rolls that have not been opened in years. If a rug spends most of its time in the middle of a well-lit, well-vacuumed room, moths rarely establish. If part of the rug sits permanently under a sofa or in a closet, that is where you find them.
How to identify moth damage
The signs, in order of severity:
- Fine, powdery debris in the pile. Frass — moth droppings — is the earliest sign. Shake the rug or brush the pile: if a fine gritty powder comes out, that is active feeding.
- Small white tube-shaped cases. The larval cases look like grains of rice or short pasta — a few millimetres long, cream or white, clinging to the base of the pile or the back of the rug.
- Bare patches. Areas where the pile has been eaten down to the foundation. Characteristically irregular — moth damage rarely makes neat shapes — and concentrated in low-traffic zones.
- Exposed foundation threads. Once the pile is gone, larvae move on to the cotton or wool warps and wefts if the infestation continues. Foundation damage makes repair harder.
Flip the rug over and check the back first. Moth damage is often more visible from beneath than from the pile face, because the larvae work from the bottom up on the wool knots.
What determines repairability
The single most important variable is whether the foundation is still intact. If the pile is gone but the warp and weft threads are undamaged, the rug is repairable — we reweave the missing pile knot by knot, matching colour, density, and direction. If the foundation is also eaten through, we first reweave the foundation, then rebuild the pile on top. That is a bigger project, but not impossible.
Area is a secondary variable. A small patch takes an hour; reweaving a quarter of a large antique takes weeks. We have restored pieces with more than 30 percent pile loss — the question is not whether it can be done, but whether the investment justifies the result.
The repair process
First we kill anything still alive. An active infestation means there are eggs, larvae, and sometimes adults distributed through the rug — the visible damage is only part of it. Moth treatment is a controlled process involving cold treatment, professional-grade chemistry, or both, depending on the piece. See moth treatment for the full protocol.
Once the infestation is eliminated, the rug is cleaned (we do not reweave into a dirty foundation), and then the reweaving begins. The process is identical to the original weaving: wool is dyed to match the surrounding field, and knots are tied individually onto the exposed warp threads, in the same knot type and density as the original. Done correctly, the repair is invisible from standing distance and difficult to spot even close up.
Prevention after repair
Annual professional inspection catches infestations before they spread. We flip the rug, examine both sides, and check the high-risk zones. Proper storage — rolled rather than folded, wrapped in breathable fabric, in a climate- controlled space — eliminates most of the risk. Regular vacuuming disturbs the environment moth larvae depend on.
Cedar and lavender deter adult moths but will not stop an established infestation. They supplement prevention; they do not replace it. For rugs with a history of moth damage, we recommend our annual moth-shield program: inspection, preventive treatment, and first-response if anything surfaces between visits. See moth treatment or rug repair for next steps. If the damage is extensive, the work usually rolls into restoration.