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Are Painted Plywood Garage Walls Better?
Drywall is code compliant and economical. But drywall absorbs moisture & water and gets dented quite easily. Can plywood be an alternative to drywall? Are painted plywood garage walls better?
Painted plywood garage walls are better than drywall on strength and impact & water resistance.
Use of plywood in a detached garage will be code compliant. Use of plywood, in an attached garage, for walls that are not adjoining living space will also be code compliant. However, you need to double check with the local building code as they can differ from place to place.
In addition, painted plywood garage walls, let you make your garage a cozy and attractive living & work space.
Here is a quick list of important quality parameters and how drywall and plywood compare.
- Strength: Plywood is Stronger
- Impact Resistance: Plywood has much Better Impact Resistance
- Installation: Drywall is Easier to Install
- Water Resistance: Plywood has much Better Water Resistance
- Fire Resistance: Drywall is Non Flammable
- Finishing: Drywall is Smoother but Plywood has a Natural Feel
- Cost: Drywall is Cheaper than Plywood
What is Plywood? What Are Its Key Features?
Plywood is an engineered wood product. There are many types of engineered wood products such as plywood, Oriented Strand Board (OSB), MDF, Composites, etc.
Within the plywood category there are many specifications, brands and qualities, each meeting specific requirements.
1. What Are Plies in Plywood?
Plywood is made from thin veneers of wood peelings from logs. The peelings are laid out in layers. Each layer is called a “ply”.
The veneer in each layer runs at right angles to the layer above or below it, giving plywood its strength. The layers are bonded together by using adhesives, heat & pressure.
The number of plies in a plywood is an important consideration. Plywood must have at least 3 plies but can have more than 3 as long as it is an odd number, such as 5 or 7, etc.
The more the number of plies, more the strength, more the weight and more the cost of the plywood sheet or board.
2. Is Plywood a Hardwood or Softwood?
The next distinguishing feature is the type of “wood” in the plywood. At a very broad level, plywood can be made from “softwood” or “hardwood”.
In the US, softwood plywood is generally made from Douglas Fir. Pine, Spruce, Cedar and Redwood may also be used.
An advantage of softwood plywood is that it is easier to work with. It is great for beginner DIYers. You just need basic woodworking tools and skills.
Softwood plywood is generally used either in the construction industry for structures. The plywood sheet that you are going to use for garage wall sheathing will likely be a softwood plywood.
Hardwood plywood may use wood shavings from ash, birch, mahogany, teak, maple & oak. Hardwood is less easily available, denser, heavier and stronger.
So plywood made from hardwood is generally used to make furniture such as cabinets, chests & built-in closets. They are also used for making doors, toys, skateboards etc.
3. What Are Exposure Ratings for Plywood?
The exposure durability classification relates to glue bond, and thus to structural integrity. Rating is an important guide for choosing the right plywood for your application.
APA approved plywood comes in 4 exposure ratings as under:
Exterior – waterproof & weatherproof
Plywood of “Exterior” rating can be used for outdoor applications and will withstand sun, rain & snow. If you are planning to make a shed in your backyard you should be using plywood of “Exterior” rating.
Exposure 1 – waterproof but not weatherproof
Plywood of “Exposure 1” rating can be used for short-term outdoor applications, such as during construction, but not for permanent structures. It is best to keep them covered with a waterproof tarp if rain or snow is expected.
Exposure 2 – moisture proof but not waterproof
Plywood of “Exposure 2” rating can be used for exterior applications provided the sheathing or the furniture has only slight exposure to moisture, but no exposure to rain. It could be used in porches, for example, in areas which are not exposed to direct rain.
Interior – not moisture proof & suitable for interior use
Plywood of “Interior” rating can be used indoors only and in dry conditions. Such plywood is not even “moisture proof”.
4. Which Grade Is Best in Plywood?
APA also grades plywood and the grading is based on the veneer finish. The grade refers to the quality and appearance of the plywood’s face and back veneers. A has the highest quality and is the most expensive, and D is the least expensive.
A-grade plywood features a smooth, sanded surface without knots. It is generally used to make furniture or cabinet doors. A-grade plywood can be painted due to it’s smooth finish and would be a good choice for painted plywood garage walls.
B-grade plywood also features a smooth, sanded surface, but may have some defects that have been patched up.
C-grade plywood is unsanded, with several minor defects & discoloration and sanding defects. C-grade plywood can be used if you are not concerned about looks or if you are going to cover it with pegboard or slatwall panels.
D-grade plywood is like C-grade plywood, only worse. That is the size of defects & discoloration is larger.
5. Can Plywood Be Fire-Resistant?
Flame Spread Rating is a test that relates to the rate at which a flame will spread along the surface of a material.
The best known flame-spread test is the “tunnel test” which has been adopted as ASTM test Standard E-84. The various regional and city building-code bodies have adopted flame-spread limitations for interior finish material based on recognized laboratory test methods.Source: Performance Panels by APA
Plywood can be Fire Retardant Treated (FRT) or Fire Retardant Coated (FRC). The difference is that FRT plywood is pressure-impregnated with fire-retardant salts and is able to inhibit combustion.
In any case the Flame Spread Rate for both FRT & FRC softwood plywood is 25 or less.
- The lowest flame-spread rate (0 to 25) is permitted for areas where fire hazard is most severe, as in vertical exit ways of un-sprinklered buildings used for public assembly.
- Materials which rate 26 to 75 are permitted in areas of intermediate severity, such as corridors providing exit ways in commercial and industrial structures.
- Materials rated from 76 to 200 are permitted in rooms of most occupancies except hospital rooms and the like.
Source: Performance Panels by APA
Please do check and make sure with the building code in your locality to ensure you are using plywood with the correct fire rating.
Plywood vs Drywall Garage Walls (Detailed Comparison)
When it comes to garage walls, Drywall or Sheetrock is the sheathing material of choice. Actually there are 10 Reasons Why It Is Better To Drywall A Detached Garage.
However, there are still many situations where you may want to use Plywood instead.
Drywall is actually quite fragile and can not take any load. So if you want to hang anything on the garage wall, you have to nail or screw onto the studs only.
Plywood is strong enough to take a reasonable amount of load. So you can hang tools etc. directly on to the plywood. This could be an important factor for you for a garage wall.
2. Impact Resistance
It is very easy to punch a hole in a drywall, because it is just gypsum paste squished together between two sheets of paper. If you are not careful with your ladder at all times you will likely rip a hole through your garage drywall.
Plywood would be able to handle that hit by the ladder. You might scratch the paint or even the plywood, but it will hold. You need that kind of strength in a garage wall, where you are parking, working and storing stuff.
3. Ease of Installation
For the same thickness (5/8″) sheet of drywall weighs 2.75 pounds per square feet as compared to 1.8 to 2.1 pounds per square feet for plywood.
Both drywall and plywood typically come as 4’X8’ boards. So it is a lot easier to move a plywood board around compared to a drywall, during installation.
Cutting a drywall is a lot easier than plywood. You can do it with a utility knife. For plywood you require a power saw.
The cutting of drywall creates a lot of fine dust which carries a great distance and settles over furniture. Cleaning up can be a nightmare. The sawdust from plywood would fall straight down. A lot easier to clean up.
4. Water Resistance
Drywall has very poor water resistance. If there is water leakage or seepage in your garage then the drywall will get soggy & disintegrate. You may have to even tear down the drywall and replace it completely.
Plywood can handle water much better. Even the “Interior” rated plywood. You can of course choose to use an “Exterior” rated plywood which is waterproof, or something in between
5. Fire Resistance
The 2018 edition of the International Residential Code (IRC) specifies the type of doors, adjoining walls and floor that an attached or a built-in garage should have.
R302.6 Dwelling Garage Fire Separation (applies to adjoining Garage Walls & Ceilings) states that
The garage shall be separated as required by Table R302.6. Openings in garage walls shall comply with Section R302.5. This provision does not apply to garage walls that are perpendicular to the adjacent dwelling unit wall.
|From the residence and attics||Not less than ½-inch gypsum board or equivalent applied to the garage side|
|From all habitable rooms above the garage||Not less than 5⁄8 -inch Type X gypsum board or equivalent|
|Structure(s) supporting floor-ceiling assemblies used for separation required by this section||Not less than ½-inch gypsum board or equivalent|
|Garages located less than 3 feet (914 mm) from a dwelling unit on the same lot||Not less than ½-inch gypsum board or equivalent applied to the interior side of exterior walls that are within this area|
You can check out Attached Garage Fire Containment blog from International Association of Certified Home Inspectors for more details.
If the sheathing is made of drywall it will meet the building code specs. Ordinary plywood will not. Will FRT plywood meet the building code? You have to check with the local authorities.
For a climate controlled garage, the walls should be insulated. Insulation materials such as fiberglass wool or rock wool have high fire resistance.
Check if the building code in your area will accept insulation batt or SPF insulation in the stud cavities behind the plywood sheathing, as adequate fire resistance.
Drywall has a smooth paper coating which is moisture resistant. Painting a drywall is rather easy as no surface preparation is required. Moreover, the moisture resistant paper coating does not absorb the paint, so you use a lot less of it.
Plywood can be finished in three different ways. Plywood can be painted to any color of your choice. It can also be stained or varnished to enhance the wood grain looks.
Some people prefer plywood because plywood can give a natural, warm feel as compared to the synthetic commercial feel of drywall.
The key reason drywall has become so popular is that it is a lot cheaper than plywood.
For example ToughRock 5/8-in x 4-ft x 8-ft Fireguard Moisture Resistant Fire Resistant Drywall Panel costs $ 22.98 at Lowes while a 5/8-in x 4-ft x 8-ft Douglas Fir Plywood Sheathing costs $ 60.39
How to Paint Plywood?
Bare plywood on garage walls does not look too good. Painted Plywood Garage Walls will improve the aesthetics of your garage. You will feel a lot more comfortable and will also be able to put your garage to other uses.
Painting of new plywood involves the following steps:
STEP 1: Filling out the Imperfections of Plywood
The surface of plywood is generally rough. Moreover if the plywood is grade C or Grade D it will have knot holes and other imperfections. These need to be filled out by using a good quality wood filler using a putty knife.
STEP 2: Sanding Plywood
Once the wood filler has dried you need to sand it to a smooth finish. But do not make the mistake of sanding only the portion where the wood filler has been applied.
Plywood surface is generally quite rough. If you want to be proud of the final painted plywood garage wall. you have to sand every square inch of the plywood.
I know it is labor intensive. But trust me the final finish will be worth it!
STEP 3: Priming Plywood is a Must
One of the biggest mistakes that many beginners make is skipping the primer coat. Skipping the primer coat may save you time, labor and some money. Or so it may seem.
The fact is skipping the primer coat will just mean you will end up using much more of the finish paint. And still the adherence will not be good and the paint may start peeling much before expected.
STEP 4: Finally 2 Coats of Finish Paint
To cover the surface completely and to get a smooth uniform finish you need to apply at least 2 coats of the finish paint. Once again using a water base latex top coat with low sheen will give your garage a nice glow.
Please keep in mind that semi-gloss or high gloss alkyd paints will not look very good on large plywood surfaces as the gloss will highlight the imperfections or waviness of the plywood.
The garage lights will also create uncomfortable glare on the painted plywood garage walls.
The bottom line is that both plywood and drywall can be used for garage wall sheathing. Drywall will meet the building codes. Plywood may not meet the building code, especially for walls adjacent to the living space. However, plywood will be quite suitable for a detached garage.
You must check with the local authorities before installation.
The top 3 factors in favor of Drywall are:
- Fire Resistance
- Ease of Installation
- Low Cost
The top 3 factors in favor of Plywood are
- Impact Resistance
- Water Resistance.
Thank you very much for reading the post. I do hope you found it informative and useful.