Why do stains appear when retexturing a wall or ceiling?
Over time stains settle into a wall or ceiling. When that area is retextured the stains photograph through causing a yellowing or browning effect. The best way to prevent staining is to apply a stain blocker, primer, and sealer.
What is the best way to store ready-mix compound for another use?
Clean sides and lid of container so no dried compound falls into the mixture. Level joint compound surface with a knife and cover container tightly. If storing, cover leveled surface of joint compound with approximately 1/2" of clean water and cover container tightly. Pour off water before reusing joint compound. Do not store in direct sunlight and protect from extreme heat and cold. The shelf life of an unopened container is up to nine months under proper storage conditions.
Can fiberglass tape be set with drying-type compounds?
No. When using fiberglass tape, only setting-type joint compounds like Sheetrock® Brand Durabond® and Sheetrock® Brand Easy Sand™ should be used for the first coat over the tape. Ready-mixed drying-type compounds can be used for subsequent finishing coats.
Can additives be mixed into joint compound?
There are various products in the market which, when mixed with joint compounds, claim to improve various performance attributes of joint compounds.
USG does not endorse the use of additives in USG joint compounds for the following reasons:
An additive can adversely affect the unique balance of the many performance attributes each joint compound has been formulated to provide.
It is virtually impossible for an additive manufacturer to know if their additive is compatible at all times with all of USG's product formulations.
USG has no control over the manufacture and quality of additives manufactured by others.
Note - For taping and finishing joints, water can be added as necessary. USG recommends adding water in increments of a half-pint to avoid over thinning.
See USG Technical Information Sheet J1716 for more information.
Can I use two different joint compounds on the same joint? Can I mix two joint compounds together to save time?
Yes, different joint compounds can be used over each other.
No, different joint compounds should never be mixed with each other.
How long does it take joint compound to dry?
Under conditions of a temperature of 70° and 70% humidity, joint compound should dry in about 24 hours. Higher humidity and/or lower temperatures will slow drying time.
What is the fire rating of joint compound?
Joint compound does not have a fire rating by itself, but does meet ASTM C475. When fire testing a wall the fire rating is not for individual products, but for all the system components together. USG Joint Compounds are used in numerous fire-tested assemblies. These are outlined in USG Publication SA100 Construction Selector.
Can ready-mixed joint compound be used on exterior applications?
No. Sheetrock® Brand Setting-Type Joint Compounds (Durabond® and Easy Sand™) are recommended to treat joints in exterior gypsum ceiling board.
What is the biggest gap between joints that can be filled with joint compound?
The maximum gap should not exceed 1/8 of an inch.