What most people call a “spider nest” on a wall is almost always a spider egg sac, a small silk pouch containing anywhere from a handful to several hundred eggs. These sacs vary widely in shape, size, and color depending on the species, but they share one thing in common: each one can release a large number of spiderlings if left undisturbed. Here’s how to identify what you’re looking at, figure out which spider left it, and remove it safely.
What Spider Egg Sacs Look Like
Spider egg sacs range from pearly white to green, brown, or russet. Some are perfectly round, others are flattened or teardrop-shaped. Most indoor sacs are small, roughly the size of a marble or smaller, though some outdoor species build sacs over an inch across. The outer layer is woven silk, sometimes smooth and papery, sometimes rough and camouflaged with bits of debris. A single sac can hold anywhere from 4 eggs to over 600, depending on the species.
Indoor egg sacs tend to appear in upper corners where walls meet ceilings, behind picture frames, along window trim, or tucked into any sheltered crack or crevice. If the sac looks like a small, pale pouch pressed flat against the wall or ceiling junction, you’re likely dealing with one of the most common indoor species.
Which Spiders Build Nests on Walls
Yellow Sac Spiders
These are the most likely culprit if you’re finding small, papery silk tubes in the upper corners of rooms. Yellow sac spiders build a flattened silk retreat where walls meet ceilings, behind frames, or in folded fabric. They hide inside this sac during the day and come out at night to hunt across walls and floors, returning before dawn. If you’re seeing small, pale spiders near your ceiling line, this is the most common explanation.
Yellow sac spiders are worth knowing about because they bite more often than most household spiders. They tend to hide in clothing, bedding, and shoes, and when pressed against skin they bite defensively. Their venom isn’t dangerous, but the bite is surprisingly painful for such a small spider. You can expect sharp pain, redness, swelling, and occasionally a slow-healing spot. Their bite is considered the most commonly reported spider bite in the United States.
Cellar Spiders
Often mistaken for daddy longlegs, cellar spiders have tiny bodies (about a third of an inch) with disproportionately long, thin legs. They build messy, irregular webs in corners, basements, and dark areas of buildings. Their egg sacs are loose clusters of eggs held together with a thin layer of silk, often carried by the mother in her jaws rather than attached to the wall. If you see a tangle of wispy webbing in a corner with a small spider hanging upside down, that’s a cellar spider setup.
Common House Spiders
American house spiders build the classic cobwebs you find in corners and along window frames. Their egg sacs are brownish, roughly teardrop-shaped, and often suspended within the web itself. You might find several sacs in one web, since females can produce multiple sacs over their lifetime, each containing successively fewer eggs.
Is It Actually a Spider Nest?
Not every structure on a wall belongs to a spider. Mud dauber wasps build distinctive tubes out of clay that are easy to confuse with spider activity at first glance. The key difference is material: mud dauber nests are hard, dry, and made of actual mud, often slightly curved and several inches long. Multiple tubes may be fused together, resembling a set of small pipes. Inside, the wasp packs paralyzed spiders as food for its larvae.
Spider egg sacs, by contrast, are made entirely of silk. They’re soft or slightly firm to the touch, lightweight, and usually under an inch in size. If you can poke it and it feels like hardened clay, it’s a wasp nest. If it feels like paper or cotton, it’s spider silk.
How to Remove an Egg Sac Safely
The simplest and most effective method is a vacuum cleaner with a hose attachment. Place the nozzle directly over the sac and suck it up along with any surrounding webbing. Then empty the vacuum bag or canister into a sealed bag and dispose of it outdoors immediately. This matters because spiderlings can still hatch inside the vacuum if you leave it. If you can’t reach the sac with a vacuum, a broom works. Sweep the sac into a bag, seal it, and take it outside.
Destroying egg sacs is the single most important step in controlling spider populations indoors. Each sac can contain hundreds of young spiders, so removing even one prevents a significant hatching event. If you spot multiple sacs, take the time to get all of them.
Why Spraying Often Doesn’t Work
Here’s something most people don’t realize: standard bug sprays are largely ineffective against spider egg sacs. Research from UC Riverside found that spider egg sac silk is highly water-repellent, so water-based pesticide sprays (which is what most household and professional pest control products are) can’t penetrate the silk layer to reach the eggs inside. The eggs survive, and spiderlings emerge on schedule.
Oil-based aerosol sprays performed far better in testing, completely preventing spider emergence by penetrating the silk barrier. But physical removal with a vacuum or broom is still faster, cheaper, and more reliable than any chemical approach. If you spray a sac and walk away thinking the problem is solved, you may find dozens of spiderlings in that corner a few weeks later.
Keeping Spiders From Nesting Again
Spiders are drawn to quiet, undisturbed spaces. The corners of rooms that don’t get much traffic, the back of a closet, a basement storage area: these are prime nesting spots. Reducing clutter in these areas makes them far less attractive. Regular cleaning, even just running a broom along ceiling corners every few weeks, disrupts the conditions spiders need to settle in.
Sealing entry points makes a real difference. Install tight-fitting window screens and door sweeps, and check for gaps around pipes, vents, and utility lines entering the house. Outside, trim back any shrubs, vines, or tree branches that touch the building. These act as bridges that spiders use to reach your walls. Move firewood piles, stacked materials, and yard debris away from the foundation.
Sticky glue traps placed flush along baseboards and in room corners serve two purposes. They catch wandering spiders before they can establish a nest, and they reveal which areas of your home have the most activity, so you know where to focus your attention. Check and replace them every few weeks for the clearest picture of what’s happening along your walls.