Introduction
Finishing drywall over OSB means applying drywall to bare OSB sheathing with proper bonding, taping, and joint methods. Before you start, confirm the OSB is clean, dry, and reasonably flat and plan how you’ll attach the drywall. This approach centers on solid adhesion and clean joints without compromising the panel.
Use the methods and materials recommended by the drywall and adhesive manufacturers, and follow their instructions for fasteners or adhesive usage. Taping and mudding joints cleanly is key, and you’ll want to check local rules and product labels for suitable compounds and primers. If anything is unsure, check the label, the manufacturer guidance, and local rules before proceeding.
Key takeaways
- Inspect OSB for moisture, stiffness, and delamination before drywall installation.
- Choose joint strategy early; plan seams away from high-humidity areas where possible.
- Use mechanical fasteners per manufacturer instructions; supplement with appropriate adhesive as needed.
- Check edge support and align drywall panels to minimize edge telegraphing.
- Taping and mud sequencing should prioritize long edges; wear eye protection.
- Account for ceilings, moisture, fire, and acoustic needs in layout and detailing.
Table of Contents
- Introduction
- Key takeaways
- Overview and Decision Criteria
- Tools and Materials Checklist
- Preparing OSB/Sheathing: Inspection and Conditioning
- Attachment Strategies: Mechanical Fastening Vs Adhesive Bonding
- Drywall Layout, Board Orientation, and Edge Support
- Joint Treatment Strategy (Taping, Mud Types, and Sequencing)
- Corners, Trim, and Transitions
- Special Conditions: Ceilings, High Humidity, Fire, and Acoustic Requirements
- Conclusion
- FAQ
Overview and Decision Criteria
Drywall can be finished directly over OSB or other sheathing when the substrate is stable and the wall is not expected to move excessively. You should consider movement, moisture, fastening reliability, and any local code guidance before proceeding. This is a quick moment to weigh the risks and decide if a substrate or additional leveling is needed.
Use a simple decision checklist: assess flatness, check for signs of moisture or deterioration, and verify that fasteners will hold over time. If the OSB shows significant movement, damage, or doubt about moisture control, plan for a proper substrate or conditioning step first. Always reference product labels, manufacturer instructions, and local rules when in doubt.
When to drywall directly over OSB
Directly applying drywall over OSB is a common practice, but it’s not always the best choice. It works well in these typical scenarios:
Dry climate: In arid regions, moisture isn’t an issue. Direct application saves time and money.
Interior walls only: Exterior walls need a vapor barrier, which OSB provides. But interior walls don’t, so direct drywall is fine.
Stable framing: If your framing is square and true, there’s no need for leveling. Direct application keeps things simple.
When to add a substrate or furring
Adding a substrate or furring strips under your drywall can solve several issues:
Leveling: If your OSB has imperfections, adding a layer of plywood or using furring strips can create a smooth surface for your drywall.
Decoupling: For walls with high sound transmission, like in multi-family dwellings, resilient channel decouples the drywall from the OSB to reduce noise transfer.
Fire/acoustic requirements: Some building codes require a specific drywall installation method or additional materials to meet fire and acoustic standards. Always check your local code.
Code, manufacturer, and warranty considerations
Before you start, make sure your installation method aligns with these:
Local building code: Check for any specific drywall installation requirements in your area. Some places have strict rules.
Manufacturer instructions: Always follow the adhesive and drywall manufacturer’s guidelines. Using the wrong product or applying it incorrectly can void warranties.
Warranty implications: Improper installation can invalidate product warranties. If you’re unsure, consult a professional to protect your investment.
Tools and Materials Checklist
Put together a DIY-focused set of tools for safe, code-compliant installation. Include measuring and cutting tools, a drill, and appropriate fasteners for the substrate and drywall. Don’t forget a utility knife, screw gun, and putty knives for finishing work.
Also assemble consumables and PPE: joint tape, joint compound, sanding supplies, dust containment, safety glasses, and a dust mask. Include cleanup items like tarps and a shop vac. Check labels, instructions, and local requirements to confirm what is permitted for your project.
Fasteners, adhesives, and tapes
Before you start hanging drywall over OSB, ensure you have the right fasteners, adhesives, and tapes. Here’s a quick checklist:
- Drywall screws: Use coarse-thread, bugle-head screws designed for drywall. They should be compatible with OSB and long enough to penetrate at least 1-1/4 inches into the studs.
- Construction adhesive: Choose a water-resistant, OSB-compatible adhesive like PL Premium or Gorilla Glue Heavy Duty Construction Adhesive.
- Paper tape: For regular joints, use paper tape. It’s cheaper and works well with standard joint compound.
- Mesh tape: For butt joints or when using setting-type compounds, mesh tape is a better choice. It’s stronger and helps prevent cracking.
- Primer: Zinsser B-I-N or Kilz Premium primer are good choices for OSB. They seal the surface and improve paint adhesion.
Quick rule: Always check compatibility with OSB and anticipated joint compound to avoid issues later on.
Compounds, corner beads, and finishing tools
Once you’ve hung your drywall, it’s time for taping and finishing. Here are the tools and materials you’ll need:
- Joint compound: Choose between setting-type (quick-setting) and drying compounds based on your project timeline.
- Corner beads: Use metal or plastic corner beads to protect outside corners from damage. They come in various sizes, so choose the one that fits your wall thickness.
- Taping knives: You’ll need a 4-inch knife for applying compound and a 6-12 inch knife for feathering edges. A 10-inch knife is usually best for wide seams.
- Sanding tools: Use a sanding screen or pole sander with 120-grit sandpaper to smooth out any imperfections before painting.
- Finishing products: For a professional finish, consider using a setting-type compound and a skim coat of joint compound mixed with a little bit of drywall mud powder.
Quick rule: Always follow the manufacturer’s instructions for mixing and application to get the best results.
Inspection and measurement tools
Before you start hanging drywall, it’s crucial to inspect your OSB substrate. Here are some tools that will help:
- Moisture meter: Check for moisture content in the OSB before installation. It should be below 12% to prevent mold growth and warping.
- Stud finder: Use a stud finder to locate the studs behind the OSB. This will help you secure your drywall properly.
- Straightedge/level: Ensure your walls are straight before hanging drywall. A 4-foot or 6-foot level is usually sufficient for this task.
- Camera/phone: Document any damage, warping, or other issues with the OSB substrate before you start working. This can help you identify problem areas and avoid them later on.
Quick rule: Always inspect your OSB substrate thoroughly before hanging drywall to prevent costly mistakes down the line.
Preparing OSB/Sheathing: Inspection and Conditioning
Inspect the OSB for signs of moisture, swelling, delamination, or soft spots. Look for unevenness and any visible movement across panels. Document any questionable areas before work begins.
Condition the substrate as needed by addressing moisture or damage according to manufacturer guidance. Plan subsequent steps based on what you find, including flattening high spots or replacing severely damaged panels. Always verify guidance on moisture limits and repair methods from the label or local code references.
Moisture and environmental checks
Before you start working with your OSB or sheathing, use this checklist to ensure it’s in the right condition. Perform these checks on a dry day to get accurate readings.
- Check manufacturer’s limits: Look up the moisture content limits for your specific OSB/sheathing product. This is usually around 19% or less, but check the label or manufacturer’s instructions to be sure.
- Use a moisture meter: Calibrate it according to the manufacturer’s instructions and test multiple spots on each sheet. A good range for OSB/sheathing is 6-12%.
- Look for warping: Check for any warped or twisted sheets. They won’t lie flat and could cause issues later.
- Inspect for delamination: Tap the sheet with your knuckles. A hollow sound indicates delamination, where the layers have separated.
- Check for mold or mildew: Look for dark spots or a musty smell. If present, treat with a suitable cleaner and let it dry completely before use.
- Ensure proper storage: OSB/sheathing should be stored flat, off the ground, and protected from rain. Check it hasn’t been exposed to excessive moisture during storage.
- Check for pests: Look for signs of pest damage like holes or chewed edges. If found, treat the affected sheets and consider using a pest repellent.
- Ventilate if necessary: If the moisture content is above 19%, allow the OSB/sheathing to dry naturally in a well-ventilated area until it reaches the safe range. Do not use heat sources to speed up drying.
Quick rule: Always check the manufacturer’s guidelines and use a moisture meter to ensure your OSB/sheathing is within safe limits before installation. Skipping these checks can lead to warping, delamination, or even structural issues down the line.
Repairing, trimming, and installing blocking
Use this checklist before you start installing OSB/sheathing to ensure a solid base for your walls. This is crucial to prevent costly rework later on.
- Inspect damaged panels: Check all OSB/sheathing panels for damage like cracks, delamination, or warping. Any issues? Replace them.
- Trim panels to size: Ensure panels fit perfectly around openings (doors, windows). Use a circular saw with a fine-tooth blade and follow the layout lines.
- Check edge conditions: Make sure edges are straight and clean. Any rough edges? Trim them smooth.
- Install blocking at edges: Add 2×4 blocking along studs at panel edges for screw hold-down and corner bead support. Space blocks every 16″ or 24″.
- Block penetrations: Install 2×4 blocking around any pipe, wire, or duct penetrations to provide solid backing.
- Check for proper spacing: Ensure blocking is spaced correctly (16″ or 24″ on center). Too close? Remove and reinstall. Too far apart? Add more blocks.
- Secure blocking: Screw blocks to studs using 3-1/4″ screws. Check that they’re tight against the stud face.
- Check for level edges: Ensure panel edges are level with each other and the top of the bottom plate. Not level? Adjust blocking or panels as needed.
Quick rule: Always install blocking at panel edges and penetrations to prevent screws from pulling out later, which can lead to costly repairs and wall failures.
Flattening and visual checkpoints
Before you start installing your OSB or sheathing, use this checklist to ensure it’s flat and free of defects. This step is crucial for a solid structure and prevents costly rework.
- Check for warping: Place the sheet on a flat surface. Look for any edges that don’t touch the ground. If you find any, check the manufacturer’s instructions or local building codes to see if it’s still usable.
- Use a straightedge for high/low spots: Lay a straightedge (like a level) across the sheet. Look for gaps between the straightedge and the sheet. Acceptable tolerance is typically 1/8″ over an 8′ span. If it’s more, you’ll need to level it.
- Leveling options: To level high spots, you can sand them down or use a planer. For low spots, shimming or furring strips may be needed. Always check the manufacturer’s recommendations before adjusting the sheet.
- Inspect for delamination: Tap the sheet with a hammer. Listen for a hollow sound, which indicates delamination (layers separating). If found, check if it’s repairable or needs replacement.
- Check for cracks and holes: Visually inspect the sheet for any cracks or holes. These can weaken the structure and should be repaired or replaced before installation.
- Moisture content check: Refer back to your earlier moisture checks. Ensure the OSB has reached the required equilibrium moisture content (EMC) for your region to prevent warping later on.
- Check for proper trimming and blocking: Ensure all sheets are trimmed to fit properly around openings, and blocking is installed as needed for added support.
- Inspect for pests or mold: Look for any signs of pest damage or mold. If found, treat the issue before installation to prevent further damage.
Quick rule: Always follow manufacturer’s instructions and local building codes when preparing OSB/sheathing. Skipping these checks can lead to costly rework, warping, or structural issues down the line.
Attachment Strategies: Mechanical Fastening Vs Adhesive Bonding
Understand the tradeoffs between screws or nails, adhesive bonding, or a combination. Mechanical fasteners provide long-term security and help resist movement. Adhesives can improve load sharing but depend on stable substrates and correct application.
Consider your situation and choose a method accordingly, keeping in mind movement control and edge support. When in doubt, consult product instructions and local rules to ensure compatibility with OSB and drywall. Verify any required substrate preparation steps from the manufacturer or label.
Fastener selection and spacing guidance
When it comes to mechanical fastening with OSB (Oriented Strand Board), you’ve got options. But remember, the goal is strength and longevity, not just getting ‘er done quick.
Screw type: Go for bugle head or trim head screws. They’re designed for OSB and won’t split it like a regular flathead might. Check the label to be sure.
Screw length: It’s a balancing act here. Too short, you won’t get proper hold; too long, you’ll hit something you shouldn’t. A good rule of thumb is screws that are about 1.5 times the thickness of the OSB. But always check your local codes and manufacturer recommendations. Safety first, kid.
Head seating: You want it tight but not too tight. Too loose, you’ll have a wobbly mess; too tight, you might split the OSB. Use a drill with a clutch set to ‘snug’ and let it do its job. If you’re going manual, don’t be a hero – stop when it’s snug.
Spacing: This is where you can really mess things up if you’re not careful. Too far apart, your OSB won’t hold together; too close, you’ll weaken the material. Aim for about 6 inches on center for most applications. But again, check your local codes and manufacturer recommendations. They might have specific guidelines based on load bearing or other factors.
Adhesive types and application patterns
For adhesive bonding, you’ll want to use a solvent-free, permanent elastomeric construction adhesive. These are flexible, strong, and can handle movement without failing. Always check the product label for compatibility with your specific materials.
Application patterns vary depending on the manufacturer’s recommendations, so always follow their guidelines. Generally, you’ll be applying beads of adhesive in specific patterns. Here are a few common ones:
1. Staggered Bead Pattern: This is like laying bricks – each bead is placed directly below the gap between the two above it. It provides good coverage and strength.
2. Straight Line Bead Pattern: This involves applying beads in straight lines, usually with a consistent spacing (like every 4-6 inches). It’s simpler but may not be as strong as the staggered pattern.
Hybrid approach (adhesive plus fasteners)
The hybrid method combines the strength of adhesives with the speed and simplicity of mechanical fasteners. It’s a great way to reduce framing deflection and screw pops.
First, apply your chosen adhesive (check types) following the manufacturer’s recommended pattern. Then, while the adhesive is still wet, drive in your screws at the specified spacing (review here). This sequence helps create a strong bond between the wood and the screw.
Be cautious not to overdrive screws, as this can cause the wood to split. Also, ensure you’re using the right size screw for your application (refresh on sizes).
Drywall Layout, Board Orientation, and Edge Support
Plan board orientation to minimize seams in critical zones and to maximize fastener coverage. Stagger joints to improve strength and reduce cracking potential. Leave consistent gaps at edges for trimming and expansion.
Ensure every cut edge has backing or blocking so fasteners have solid support. Align edges with existing framing where possible and check for flush transitions with trim. Confirm these practices with manufacturer instructions or local guidance if unsure.
Board orientation and seam placement
When hanging drywall over OSB sheathing, align the panel’s long dimension parallel to your framing. This reduces the number of joints you’ll need to tape and finish.
Stagger seams like bricks in a wall. If one panel ends on a stud, start the next row with a half-stud offset. That way, you won’t have continuous vertical joints over studs, which can crack under stress.
Use 1/4″ or 3/8″ drywall screws to secure panels at 6″ to 8″ on-center along studs. This ensures a solid bond and helps prevent warping.
End gaps and edge treatments
Leave 1/8″ to 1/4″ gaps at panel ends for expansion. Too little space can cause joints to telegraph, while too much leaves visible gaps.
At ceilings, use 1/2″ to 3/4″ gap filler strips to maintain the proper gap size and support panel edges. At floors, leave a 1/8″ to 1/4″ gap for expansion and install a suitable trim piece.
Around openings like doors and windows, follow manufacturer guidelines for edge treatments. Typically, you’ll need to use special corner beads or edge trims to protect edges and simplify finishing.
Handling inside corners, returns, and reveals
At inside corners, use 90-degree corner beads to protect the joint and simplify taping. Secure them with drywall screws or adhesive, following manufacturer instructions.
For reveals (where one wall meets another at a slight angle), use angle beads. Secure them in place using adhesive or screws, ensuring they’re flush with the panel surface.
At returns (where a wall meets the ceiling or floor), use return trims. Install them after hanging panels to ensure a tight fit and protect panel edges. Always check manufacturer guidelines for specific installation methods.
Joint Treatment Strategy (Taping, Mud Types, and Sequencing)
Outline a step-by-step plan for taping and mudding tailored to OSB substrates. Select tape and compounds that suit your environment and drying conditions. Follow embedding and layering practices that promote a smooth, crack-resistant surface.
Clarify sequencing: embed, apply setting or drying compounds, and finish with a final skim coat. Avoid guessing on curing times by checking product data and local requirements. If you are unsure, refer to the label, manufacturer instructions, and code guidance.
Tape selection: paper vs mesh
When it comes to taping OSB (Oriented Strand Board) joints, you’ve got two main tape options: paper and fiberglass mesh. Both have their pros and cons, so let’s dive in.
Paper Tape: This is your classic, tried-and-true option. Paper tape is strong and provides a solid base for your joint compound. It’s great for wide joints or when you need extra strength. However, it can be a bit trickier to apply, especially on larger areas.
Fiberglass Mesh Tape: This stuff is like magic for DIYers. It’s easy to apply and can span small gaps without tearing. Plus, it provides excellent reinforcement for your joint compound. But, it might not be the best choice for wider joints or when you need extra strength.
So, which one should you choose? If you’re working with wide joints or need some serious strength (like on exterior walls), go with paper tape. For smaller gaps and easier application, reach for the fiberglass mesh. Always check your product labels and manufacturer instructions to be sure.
Compound selection and coat sequencing
First off, you’ve got two types of joint compounds to choose from: setting-type and drying. Check the product label to be sure.
Setting-type compounds set up quickly, usually within 24 hours. They’re great for first coats (bed coats) because they stick well to tape and substrate. But they’re a pain to sand due to their quick set time. Use them in controlled environments where you can keep the temperature above 50°F (10°C).
Drying compounds, on the other hand, take longer to cure – up to 72 hours. They’re easier to sand but don’t stick as well to tape or substrate. Use them for final coats (finish coats) where a smooth surface is crucial. They can be used in cooler temperatures, down to around 40°F (5°C).
Now, let’s talk sequencing. You’ll typically apply three coats: the first two are bed coats, and the last one is your finish coat.
The sequence goes like this:
- Apply your first bed coat with a setting-type compound. This locks in your tape and provides a base for your second coat.
- After it sets, apply your second bed coat with a drying compound. This helps to fill any voids left by the first coat.
- Once that’s dry, sand lightly to remove any high spots or imperfections.
- Apply your final finish coat with a drying compound. This gives you that smooth, professional look.
Embedding and feathering techniques to prevent cracking
When embedding tape into mud, press it in firmly. You want the tape to be fully embedded, not just sitting on top of the compound. Use a straight edge or a trowel to ensure even pressure.
Feathering is key to preventing cracks. Here’s how:
First coat (skim): Feather out to about 1″ wide. This helps blend the tape into the joint and provides a good base for the next coats.
Second coat: Feather out to about 2-3″ wide. This builds up the joint and starts to hide the tape.
Third coat (finish): Feather out to about 4-6″ wide. This gives you a smooth, finished look.
Corners, Trim, and Transitions
Describe proper installation of metal and plastic corner beads, including how to seat and secure them for a crisp edge. Address butt joints around window and door trims to minimize stress points. Plan transitions where drywall meets other wall materials to reduce cracking risks.
Confirm that trims and beads are compatible with OSB substrates and your chosen joint system. Avoid shortcuts by following manufacturer directions and local rules for corner protection and transition details. Verify any special recommendations from product labels if unsure.
Corner bead selection and installation
Choosing the right corner bead is crucial for a durable, crack-resistant finish. Rigid metal beads provide strength but can be tricky to install on OSB/sheathing. Flexible beads or vinyl options offer easier installation but may not hold up as well over time.
Metal beads: Use 1/8″ thick for standard corners, 3/16″ for high-traffic areas. Fasten with drywall screws every 4-6″. Embed the bead in joint compound, let it dry, then sand smooth.
Flexible/vinyl beads: These are self-adhesive and easier to install. Apply a thin layer of compound over the bead for extra protection. Avoid using on corners subject to heavy impact.
Trims, reveals, and termination points
Proper detailing at trims ensures a clean finish and allows for movement. At windows/doors, use butt joints: end the drywall board short of the trim, apply compound, and sand smooth.
For baseboards, leave a 1/8″ gap between drywall and base to accommodate expansion/contraction. Apply caulk in the gap after painting for a finished look.
With built-in casework, use reveals: offset the drywall behind the trim by 3/4″. This hides any gaps and allows movement at the trim.
Transition to different substrates and materials
Transitions require careful planning. Incorrect material choices can lead to cracking, staining, or weak bonds.
- Tile backer: Use 1/2″ cement board. Fasten with screws every 6″. Seal seams with thinset mortar before tiling. Avoid using drywall as tile backer due to moisture issues.
- Plaster: Apply a thin layer of joint compound over the drywall, let it dry, then apply plaster. Ensure both surfaces are clean and primed for good adhesion.
- Existing drywall: Remove any loose or damaged material. Apply joint compound to fill gaps, let it dry, then sand smooth. Prime before taping and mudding.
Special Conditions: Ceilings, High Humidity, Fire, and Acoustic Requirements
Note adjustments needed for drywall on ceilings and in spaces with higher humidity or temperature swings. Prepare for potential moisture control challenges and ensure fasteners and trim support accommodate these conditions. Consider how these factors affect the chosen finish system.
Account for fire-rated assemblies and acoustical goals by selecting appropriate materials and installation methods. Confirm that your approach meets local code and project requirements. Always verify with product labels, manufacturer guidance, and local authority rules when in doubt.
Ceilings and multi-directional movement
Ceiling drywall presents unique challenges. Gravity pulls down on the panels, causing sagging over time. This can stress joints and cause cracking.
To combat this, consider using thicker drywall panels, like ½” or ⅝”. They’re stiffer and less prone to sagging.
Also, use additional fasteners. Screw every 6″ along the edges and every 12″ in the field. This helps distribute the weight evenly.
For extra support, consider using adhesives. Apply construction adhesive to the OSB before hanging the drywall. It bonds the panel to the substrate, reducing movement.
High-humidity and wet-room considerations
Bathrooms and kitchens are high-humidity areas. Regular drywall can absorb moisture, leading to mold or mildew growth.
Use moisture-resistant drywall. It’s green on the face and has a moisture barrier on the paper backing.
Apply a layer of vapor control paint over the drywall seams. This seals the joints, preventing moisture from getting in.
Remember, OSB can swell when exposed to high humidity. Check product limits and allowances for your specific OSB before installing.
Fire and acoustic assemblies
Some spaces require fire-rated or soundproof drywall assemblies. Always check local building codes first.
For fire ratings, you might need double layers of drywall with specific fire-resistant compounds between them. Consult code tables for exact requirements.
For acoustic control, consider using soundproof drywall or adding a layer of acoustic board behind the drywall. These can reduce noise transfer significantly.
Always follow manufacturer systems and guidelines when installing these specialized assemblies. They often require specific taping, mudding, and finishing techniques.
Conclusion
Finish around OSB with drywall carefully to keep joints smooth, edges solid, and ceilings and walls safe from movement. A durable surface starts with clean, conditioned sheathing, solid fasteners or adhesives, and proper joint treatment that resists cracking and water issues.
Check these steps in order: confirm the OSB is clean and dry, choose attachment method appropriate for the wall and local conditions, lay out panels with proper orientation and edge support, tape and mud in the recommended sequence, and finish corners, trim, and transitions with tight fits. Test a small patch first, then proceed section by section, maintaining even pressure and keeping mud workable and clean as you go. Keep high humidity and fire or acoustic requirements in mind as you plan each step.
Common mistakes to avoid are trying to rush joints without proper mud or tape, using mismatched fasteners or weak adhesive bonds, and neglecting edge support at corners or around openings. Always wear eye and dust protection, work with a helper when lifting or aligning large sheets, and verify the wall is fully dry and stable before applying mud or paint. If you encounter unusual framing, persistently damp conditions, or complex ceilings and transitions, call a pro for guidance and avoid irreversible damage.
If you know when to step back and call help, you’ll keep costs down and results repeatable. When in doubt about structural integrity, moisture risk, or code requirements for fire and acoustics, bring in a pro sooner rather than later and keep the project moving with confidence. Stay focused, execute the plan in small, safe steps, and you’ll finish with a solid, professional-looking wall that lasts.
FAQ
Is adhesive bonding alone enough to attach drywall to OSB or is mechanical fasteners needed?
Always check the adhesive instructions and OSB manufacturer guidance. In practice, use a combination of adhesive and mechanical fasteners for a reliable install, and make sure the OSB surface is clean and flat.
How should I handle joints and seams on OSB before hanging drywall?
Fill gaps and create a solid edge with appropriate backing. Use the recommended joint tape and compound, and follow the product’s curing times and layering guidelines—no shortcuts.
What should I do about moisture or high humidity when finishing drywall over OSB?
Make sure the OSB and framing are dry before starting. If humidity is a concern, address the source and consider a vapor barrier or breathable coatings as advised by the manufacturer or local rules.
Any tips for corners and transitions when OSB is the substrate?
Install proper corner beads or trim, and ensure edges are clean and supported. Use backing or blocking at outside corners to prevent nail/screw pops and provide a solid base for tape and mud.