How to Build a Paint Booth for Your Garage

Introduction:  The directions for this paint booth came from bits and pieces of other booths I saw on the net, combined with some of my own ideas.  I am not a carpenter or electrician, as you will see, but this is an easy enough project that nearly anyone can accomplish with a little time and motivation.

View from outside of garage

View from inside of garage (please ignore junk around it)

The booth being shown here is not enclosed, so it does not use positive air pressure to keep the air clean.  This booth has an open end so that it is easy to use and does not occupy a massive amount of space.  It can be easily disassembled by removing the pins from the hinges during times of disuse.  Though this method might not be adequate for some applications, it is more than enough for the painting I do.  By pulling away the over-spray with a fan, the finish stays nice and smooth.  If you wanted an enclosed booth in the future, it would be easy to adapt this one by adding extra panels.

This is not the cheapest booth you can make.  There are directions for many booths online using PVC tubing and plastic sheeting.  I consider these to be more for one-time use, such as for painting a car.

CAUTION:  This paint booth is intended for non-volatile paints and finishes.  Use of such items in an enclosed space without proper ventilation and a fan meant for flammable compounds is potentially dangerous.  Please read the instructions on finishes and paints CAREFULLY before using this booth.  No matter what paint is used, always vent to the outdoors when using a paint sprayer.

These are the items you will need to construct the booth:

14 8' 2"x4"s
14 8' 1"x2" furring strips
1   8' 1"x12" board
4   4'x8'x1/2" sheets of R-Matte Plus Foam Insulating Sheathing
2"  Screws
3"  Screws
20" High Velocity Floor Fan
Weatherproof toggle switch cover, toggle switch, and switch box (optional items)

The wood can all be the cheapest you can find.  I got kiln-dried whitewood studs for my 2x4s at $2.57 apiece.  The furring strips were $.78 apiece.  The 1x12 board was also whitewood, and cost $8.15 for one.

The sheets of rigid insulation cost $10.58 each, which is a good deal when compared to most other sheathing.  The advantage of the R-Matte is that it is quite rigid, lightweight, cheap, and easy to work with.  You can use other foam insulation, but you will have to buy thicker, more expensive stuff to get the same results.  Wood works as well, but it is heavy and expensive.

The fan can be purchased for between $40 and $60, depending on quality.  You can use a box fan, but I couldn't find one that wasn't a cheap piece of junk.  They don't have much power, so you'd need more than one to do the same job as one high velocity fan.

The weatherproof switch is optional.  I put one in so that I wouldn't have to constantly plug and unplug the cord.  Since it faces the inside of the booth, I figured that a toggle cover would help protect the switch from paint.  I think I paid $7 something for the switch and cover, and a bit less than that for the box.

With tax, including the screws, the total came to around $200.  I live in SE Wisconsin, so the amount could vary by region.  That's not a bad price considering you end up with a permanent, sturdy, functional paint booth that doesn't take up an entire garage.

This is the list of tools you will need:

Saw for cutting the wood--preferably a compound miter saw
Drill, drill bits, driver bit for screws
Measuring tape
Pencil
Straightedge for marking lines
Utility knife
Screwdriver for electrical box

Construction Steps:

Step 1:  The Frame  Create 3 identical rectangles using the 2x4s.  The interior dimensions will be 48" x 96", which will be enough to allow the 4'x8' sheet to fit perfectly. If possible, add 1/4" for a little bit of wiggle room.  My garage was too short for an 8 foot tall booth, so I had to make the booth 7 1/2 feet tall.  All I had to do was cut a bit off of the ends of the sheathing.  I used 3" screws to hold together the 2x4s.

It is important to make sure that the rectangles are squared before continuing.  To do this, simply measure both diagonals.  They should be equal.  If not, push on a corner while it is against a wall to try and get it into shape.  You may need another person to help hold it if it won't stay.  When it is squared, use the 2" screws to attach some wood lath or scrap pieces of wood to opposite corners (see photo) in order to secure it in the correct shape.

NOTE:  Pre-drilling holes for the screws is always a good idea.  I did not have to pre-drill for the 2x4s, but I did for everything else.  There will be cracking otherwise.  I am going to use this moment to advocate the use of star screws.  I use them for everything now because they WILL NOT STRIP.  They will break before stripping, which takes a lot of torque.  I use Deck-Mate, but there are other brands.

One of the 3 panels, squared using scrap 1x2s.

View of how wood joins

Star Head Screw

Step 2:  Attaching the hinges:  I think it is probably easier to attach the 3 panels together before working on the fan and wood lath.  It could be done later if so desired.  You may want someone to help hold the panels while attaching the hinges.  I put two between each panel for a total of four hinges.  I attached them with 2" screws.  Butt the panels together at a 90 degree angle and then screw the hinges on.  I put each one about 2 1/2 feet from the top and bottom.  If a permanent form is desired for the booth, the hinges could be substituted with wooden cleats that keep the panels at fixed angles.

Close-up of one of the hinges.

Step 3:  Fan Enclosure  The fan essentially sits in a box that is mounted between 2 2x4s.  I put together the box so that the fan fit in with 1/4" to 1/2" on all four sides.  To measure the distance needed, remove the fan from the base and leave the rubber spacers on the fan.  It is easier to remove the fan and measure it if the front grille is removed.  Measure from the outside of one spacer to the outside of the other.  Put the box together with 2" nails.

Fan view from inside booth.

Fan view from outside booth.

Step 4:  Mount the Fan Box  Once you have completed the box for the fan, 2 2x4s need to be inserted vertically to hold the box.  After those are in place, a 2x4 needs to be placed horizontally between them for the fan box to rest on.  The fan box can now be attached using 2" nails.  The box should be flush with the 2x4s on the inside of the booth, and stick out the back side.  The last thing to do is to put a horizontal 2x4 on top of the box between the 2 vertical 2x4s and attach it into place.

View of mounted box.

Step 5:  Furring Strips  When the 2x4 framework and the fan box are put together, it is time to attach the furring strips.  They get mounted directly in the middle on the inside of all 2x4 surfaces.  These will provide a surface to attach the foam sheathing.  I left a small section without furring strips where the switch box was installed.

The furring strips can be seen here attached to the 2x4s.

Space left in lath to mount switch box.

Step 6:  Mounting the Fan  To mount the fan, the front grille must be off, and it is advisable to have someone else help hold it.  Measure and mark the center points on the right and left inside surfaces of the fan box.  Hold the fan up to the marks to make sure that the fan will be centered in the box when it is attached.  The carriage bolts that came with the fan will quite probably be too short to make it through the wood to the nut on the other side.  I had to get longer bolts in order to make it work.  They don't have to be carriage bolts, but it is advisable.

Once you have the marks correct and you have the right bolts, drill a hole all the way through both marks.  The hold should be the same size as the bolts.  You can then mount the fan and tighten the nuts.  If there is a gap between the rubber spacers and the wood, you can fill it with some washers (see photo).

Note:  Be careful to mount the fan facing outward so that you don't have to do it all over again.

Washer added as spacer between the rubber spacer and the wood.

A nut with a washer on the outside of the fan box.

Step 7:  Mounting the Filter  To mount the filter, all you need to do is surround the outside edge of the fan box with wood strips that are at least 1/8" deeper than the filter is wide.  It doesn't have to be a super-tight fit, as the fan will suck the filter tight against the wood.  Leave the top edge open to insert the fan.  You then need to put strips of wood along the left and right edges to hold the filter in.  The bottom doesn't need a second strip as it only keeps the filter from sliding down.

View of 2 wood strips that form channel for filter to slide into.

View of all wood strips in place for filter. 

Filter sliding in the track.

Step 8:  Preventing air from Circulating Back into Fan  Around the edges of the fan there is plenty of space for air to come back in.  If this happens, you will not get as good of suction.  I tested it by sprinkling sand in from the outside and it got sucked right back into the fan and into my face.  That is why I made the curved pieces for the corners.  Just get some scrap 1x10 or 1x12 lumber (or buy a small quantity), make a template from some cardboard, then trace onto the wood.  Make sure that the wood does not touch the fan as this will  make vibration and noise.  Attach with 2" nails from the outside.  I needed an extra set of hands for this procedure.

Note:  If you think the fan will provide enough suction as-is, you may elect to skip this step.

One of the curved pieces installed to prevent air from re-entering.  Notice the gap between the fan and the wood.

Step 9:  Installing the Foam Insulation Board  Installation of the foam board is the easiest step.  Simply measure the size you need, mark the foam with a straightedge, and cut the foam with a utility knife along the line.  When a panel is put into place, simply use some screws to attach it to the lath behind it.  I used a total of 8 screws (4 in each corner, and 4 at the middle of each length) to attach the large panels.  Use common sense for the smaller ones.  Keep in mind that the switch box will need a small opening if you decide you will be installing one.  The fourth panel is meant to simply lay on top of the booth to help direct air and to help keep contaminants from falling onto painted surfaces.

Foam Panels in Place.

Step 10:  Wiring the switch  This is an optional part if you just want to plug in the extension cord when you want to turn the fan on and off.  Since the switch for the fan is behind the filter, the only way to turn it on and off via a switch is to wire the fan cord to a switch which then runs to an extension cord.  I mounted a box, cut the fan cord, wired the cord to a light switch, wired the cut end of the cord out the other side, and screwed the cover on.  If you need me to explain further, I suggest you get someone familiar with electrical to install it for you.  You do not want to do it wrong and electrocute yourself.  The cord runs from the fan through a hole in the top of the fan box to the switch box.  A small section of foam board needs to be cut out so that the switch can be accessed from inside the booth.

Switch box after wiring completed

Weatherproof switch cover.

Step 11:  Get Painting!  Once you have a drop cloth down and some proper lighting, you are ready to start painting.  This booth will last for many years, and if the foam panels get too covered with paint, they are easy to replace.  You may find some adjustments are necessary for your situation, but this will give you a good start.  Enjoy!