In Stock • 1668 1st Ave, Upper East Side
USG Structo-Lite Basecoat Plaster
The perlite basecoat that rebuilds pre-war plaster walls — the material a Manhattan apartment actually needs when a wall opens up, and the one most stores do not carry. $26.99 for the 50 lb bag, on the shelf today.
See the bag →What Structo-Lite actually is
USG Structo-Lite is a mill-mixed gypsum basecoat plaster with perlite aggregate. Perlite is a volcanic glass that is expanded with heat until it is light and porous, which is why a bag of Structo-Lite weighs about half what an equivalent sanded plaster does and why it can be built up thick without sagging off the wall.
It is a basecoat. That is the whole point of it. It is the material that goes on first and rebuilds the body of the wall, and then a finish coat or a skim of joint compound goes over the top of it. You add water only — no sand, no lime, nothing else to buy.
Why pre-war Manhattan needs it
Most Upper East Side apartment buildings went up before drywall existed. Those walls are plaster over lath: thin strips of wood, or later metal mesh, nailed across the studs, with wet plaster pushed through the gaps so it curls around behind and locks itself on. That curl is called a key, and it is what holds a hundred-year-old ceiling up.
When a section of that wall fails — a leak from upstairs, a ceiling crack that finally lets go, a contractor opening a wall for pipe — you are not patching drywall. You are rebuilding a plaster wall, and it needs a plaster material.
Structo-Lite vs joint compound
Structo-Lite (basecoat)
Builds depth. Goes on thick in one pass, bonds to lath and masonry, sets hard rather than just drying out. This is the body of the repair.
Joint compound (finish)
Smooths the surface. Thin coats only, sanded flat. Shrinks and cracks if you try to fill depth with it. This is the last 1/8 inch, not the wall.
Coverage: how many bags do I need?
One 50 lb bag of Structo-Lite covers roughly, at standard basecoat thickness:
| Substrate | Coverage per 50 lb bag |
|---|---|
| Gypsum lath | ~140 sq ft |
| Unit masonry | ~109 sq ft |
| Metal lath | ~89 sq ft |
Metal lath eats the most because the plaster has to push through the mesh and form its keys behind it before it starts building thickness on the face. Cured compressive strength is around 700 psi.
For a typical apartment patch — a few square feet of ceiling, or a wall opened for a pipe run — one bag is almost always more than enough. Buy the one bag.
How the repair goes, in order
- Clear back to sound material. Take off anything loose or crumbling until what is left is solid and still keyed to the lath.
- Check the lath. If the wood lath is broken or missing, it has to be replaced or bridged before any plaster goes on — plaster with nothing to key into will not stay up.
- Mix and build with Structo-Lite. Add water only. Fill to just below the surrounding surface, leaving room for the finish coats.
- Finish over the top. A skim of joint compound, feathered wide, then sand and prime.
Follow the mixing ratio and set times printed on the bag — they are the manufacturer's and they are the ones that matter. If you are unsure what you are looking at behind the damage, take a photo and bring it in. We would rather look at it than guess.
What else the job usually takes
All in stock at 1668 1st Ave:
- USG Sheetrock Plaster of Paris, 25 lb — $29.99, for fast small patches and casting
- USG Easy Sand 45, 18 lb — $19.99, a setting compound for the intermediate coats
- USG Joint Compound, 3.5 qt — $14.99, for the finish skim
- Adfors FibaTape, 150 ft — $7.99, to bridge cracks and edges
- Hyde 10 in Taping Knife — $29.99, for feathering wide
Where to buy Structo-Lite in NYC
Here, off the shelf. New York Paint & Hardware, 1668 1st Avenue (at E 87th St) in Yorkville on the Upper East Side, family-owned since 1986. Open Monday to Saturday 8:00 AM to 6:30 PM and Sunday 10:00 AM to 6:30 PM.
Stocking a basecoat plaster is unusual for a neighborhood hardware store — the big boxes generally do not, because outside of pre-war housing stock almost nobody asks for it. In this neighborhood, people ask for it constantly.
Pick it up in store, or take free same-day Manhattan delivery on orders over $100. Call 212-249-1614 to check we have the bag count you need before you come over.
USG Structo-Lite, 50 lb — $26.99 →
Structo-Lite FAQs
What is Structo-Lite used for?
It is a gypsum basecoat plaster used to rebuild the body of a plaster wall or ceiling before a finish coat goes on. In New York that usually means repairing pre-war plaster-over-lath walls, where joint compound would shrink and crack.
How much does Structo-Lite cost?
$26.99 for the 50 lb bag at 1668 1st Ave. One bag covers roughly 140 sq ft over gypsum lath, 109 sq ft over unit masonry, or 89 sq ft over metal lath.
Can I use Structo-Lite over drywall?
It is formulated as a basecoat over lath and masonry, not as a skim over paper-faced drywall. If your wall is drywall, you want joint compound, not a basecoat plaster. If you are not sure which you have, send us a photo.
Do I add sand to Structo-Lite?
No. It is mill-mixed with perlite aggregate already in it. Add water only.
Is Structo-Lite the same as plaster of Paris?
No. Plaster of Paris sets very fast and is used for small patches and casting. Structo-Lite is a basecoat with a longer working time, made to be built up thick over lath. We stock both.
Why does my ceiling keep cracking after I patch it?
Usually one of two reasons: the depth was filled with joint compound, which shrinks; or the lath behind the damage is broken, so nothing is holding the patch. Both are worth checking before you patch it a third time.
Do you deliver?
Yes — free same-day delivery across Manhattan on orders over $100. A 50 lb bag is heavy; delivery is often worth it.
Working on drywall too?
See our drywall and sheetrock page — we sell board by the single sheet and cut every sheet in half free so it fits your elevator.