Technically, you can cut any Mullen, though only the alcove models are designed with cutting in mind. An accessory kit is available that replaces the cutaway upstand of an alcove Mullen for a watertight enclosure. Cutting any other Mullen will create a bunch of problems, and render the product useless. To make a cut, use a reciprocating saw, a hand-held jigsaw, or a circular saw. Equip the saw with a fine-toothed blade to reduce the chance of chipping along the cut edges. The underside of each alcove model even has guidelines to help you make straight cuts. Accessory kits are available to convert a corner Mullen to an alcove Mullen. The illustration below shows the underside of a 72-3/8” long Mullen, which can be cut in a 10-3/4” area at both ends.

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All Mullens are 1-1/8” thick.

Yes they are (please click here for example). When installed level with the finished surrounding floor, a Mullen offers a perfect ‘0’ entry threshold.

Yes, Mullen shower bases are waterproof.

Mullens have a finished top surface, making it unnecessary to add tile or vinyl.

Sorry, no. We carry the full line of Mullen sizes and configurations. And the manufacturer does not make custom units.

Every Mullen accepts a standard 2” PVC drain.

Sorry, no. White is the only color.

The top is over ¼” thick while the underside of a Mullen is comprised of many crisscrossing ribs that form a waffle pattern. The ribs make the Mullen very strong and rigid while reducing weight.

There is only one pattern available. It consists of raised, small round bumps covering the entire base. It’s easy to clean and provides good traction.

You can, and there are situations where this makes the most sense. If you install a Mullen on the subfloor, ideally you want to build up the area surrounding the Mullen so the finished floor is level with the top surface of the Mullen. We do offer a ramp for the Mullen if you choose not to build up the surrounding floor. Keep in mind that you will need to cut a hole in the subfloor about 6” in diameter to allow for the drain connection and the elevated ring around the drain hole on the underside of the Mullen.

Use construction adhesive (like PL400 or Liquid Nails) between the Mullen and joists or wood subfloor. Thinset mortar is the best choice for concrete installations, though you could use thinset mortar on wood subfloors as well. Thinset mortar, given its thick consistency, is a good gap filler if there is unevenness or gaps between the subfloor and the underside of the Mullen. In addition, you’ll want to secure the Mullen with screws to the joists or subfloor, and wall studs. There are pre-bored fastening holes hidden by the clamping bar that you can use to secure the Mullen to the joists or subfloor. For securing to wall studs, simply drill pilot holes through the Mullen’s nailing flange at stud locations and drive a screw at each location. We always recommend using stainless fasteners in wet area installations.

Each leading edge of a Mullen is equipped with a clamping bar that fits into a channel (see illustration below). Clamping bars are held in place with screws (supplied) spaced about 8” apart. Remove the screws to release a clamping bar and reveal a channel. Accessories like the tile adapter and ramp are equipped with an edge that fits into the channel to create a crisp, clean, watertight transition between the Mullen and the surrounding floor. The channel is also ideal for holding the edge of vinyl floor coverings. Plastic caps, supplied with every Mullen, are used to cover the clamping bar screw holes. With the clamping bar secured into the channel, entry into a Mullen is level and barrier-free.

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Glass reinforced plastic (GRP).

Absolutely level! The angled planes of a Mullen offer plenty of pitch to speed water to the drain, but every degree that’s lost to an out-of-level installation affects drainage performance.

Use the flat areas around the perimeter of the base, or the top edges of the upstands.

Setting a Mullen on joists requires care and is the most critical part of the installation. A Mullen must be level, and all edges plus the drain area must be supported. Install 2” x 4” or 2” x 6” blocking to support all Mullen edges and the drain opening (be sure the drain hole blocking will be no closer than 2” from the perimeter of the hole). Once all blocking is installed, set the Mullen in place and check for level. You may need to shim or shave joists to achieve a level, completely even Mullen installation.

You have a couple of options. As always, we recommend installations that avoid creating a barrier or change of elevation between the shower and the surrounding floor. You can remove concrete to a depth of 1-1/4” in the area where the Mullen will go. We do this with a special concrete-cutting saw and blade (item code ARC555) First outline the Mullen position on the floor then cut along the outline. Next, make scoring cuts no more than 1” apart inside the perimeter cuts. We remove the remaining waste with an electric hammer drill and chisel. You can use thinset mortar to install the Mullen in the recess. Alternatively, you can install the Mullen on top of the concrete and build up the surrounding floor to end up with a level entry to the shower, or use the ramp accessory to allow entry into the shower. Of course, with any of these methods you may still have to remove concrete for the drain.

Use ordinary cleaners as you would for acrylic bathtubs and showers. Glass reinforced plastic is tough, though abrasive cleaners and caustic chemicals may scratch and discolor the surface.

You can do about anything you want to cover and decorate the walls of your Mullen shower. Tile, acrylic panels, pebbles, marble, granite, etc. are all fine choices. If tiling, we recommend waterproofing the walls beforehand to prevent any moisture from penetrating the substrate materials.

The manufacturer offers a limited lifetime warranty to the original purchaser of a Mullen shower base, which covers material defects and workmanship.

The best way to understand this is to look at illustrations of the two types (see below). Simply put, an alcove Mullen is designed to fit into an area surrounded on three sides by walls (comparable to a typical bathtub setup). A corner Mullen has two adjacent sides designed to butt against walls and two sides that remain open for entry to the shower. Kits are available to convert a corner Mullen for use in an alcove, however, the size of a corner Mullen cannot be altered.

See example of difference

Yes you can cut a Tuff-Form. A reciprocating saw, a hand-held jigsaw, or a circular saw will all do just fine. Using a fine-toothed blade reduces the chance of chipping along the cut edges. Do not cut any closer to the drain hole than 6”.

Each Tuff-Form is 7/8” thick.

The Tuff-Form was designed to work with tiled floors. Codes in most areas for tiled floors include a 3/4”-thick subfloor topped by a 1/4”-thick tile backer board. This makes the floor surrounding a Tuff-Form about 1” in elevation. Sanding the tile backer board just outside the Tuff-Form to extend the Tuff-Form’s pitch is the perfect scenario for blending the entire bathroom floor into a continuous, single-level, accessible wetroom.

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Yes, Tuff-form shower formers are waterproof. Once installed, however, all transitions between the Tuff-form and the surrounding subfloor and walls must be covered with waterproofing membrane and joint reinforcing fabric, which are part of the Tanking Kit. Also, a drain gasket must be installed using the waterproofing membrane. By the time you have the edges covered and the drain gasket installed, you’ll have coated 50% or more of the Tuff-form, at which point it’s just easier to cover the whole surface with the waterproofing membrane. The membrane also provides a good bonding surface for thin set mortar or vinyl adhesive.

Sure, a T-F is a perfect choice to use as an overflow catch basin.

Sorry, no. We carry the full line of Tuff-Form sizes, though we hasten to add that the size of the Tuff-Form does not limit the size of a shower. We’ve developed techniques for building larger showers using a Tuff-Form and other materials. The Tuff-Form establishes the pitch planes and drain site, and the other materials are used surrounding the T-F to make any size shower imaginable.

We wish we could say yes, but the fact is, it’s only available in the satin stainless finish. You could have the grill custom finished by a professional to achieve a different look, but that’s about the only choice available.

The top of a Tuff-Form is over 1/4” thick, and the underside of the Tuff-Form is comprised of many thin ribs that form a waffle pattern (see illustration below). The ribs make the formers very strong and rigid while keeping the weight low. As it is, Tuff-Forms weigh about 3.5 pounds/sq. ft.

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You can do this and it will be fine, though the Tuff-form is designed to span 16” on-center joist systems so that you can install it directly on the joists. If you install a Tuff-Form on the subfloor, you should build up the surrounding area so it’s approximately level with the top surface of the Tuff-Form (having the surrounding floor about 1/8” higher than the T-F is perfect). You will need to cut a hole in the subfloor 8” in diameter to allow for the strengthening ring around the drain hole on the underside of each Tuff-Form. Optimally, there should be no barrier between the bathroom floor and the shower floor in the finished bathroom.

No you don’t. There are a lot of holes, and they are there for convenience. The screws are there just to hold the Tuff-Form in position while the adhesive cures. Once the construction adhesive (like PL 400 or Liquid Nails) cures there is little need for the screws. In fact, if your project is located in a humid area, we recommend withdrawing all but one screw per edge of the T-F once the adhesive cures. This way the screws will not bind the Tuff-Form as the wood around it adjusts to seasonal changes in airborne moisture. Construction adhesive has enough flexibility to allow such slight movement.

We use #9 or #10 screws that are 2” long.

The manufacturer has developed a waterproofing formula specifically for the Tuff-Form wetroom and stands behind this system. Many waterproofing products will not bond well to glass reinforced plastic (GRP), the material used to make Tuff-Forms. ARC has tested and/or investigated many of the waterproofing products on the market and has found that this system is the best. The Tuff-Form Wetroom Kits exceed our critical standards, which is why we carry them and recommend them. If you use any other products, you’re on your own.

Yes, you can. The point load rating on the Tuff-Form is 4,000 pounds/sq. inch, so it can handle even the smallest mosaic tile, pebble, and glass coverings, any wheelchair or shower chair. In fact, you probably need to consider joist structure reinforcement well before you get concerned about the Tuff-Form. We do recommend tile that’s 2” square or smaller in the shower area. Larger tiles that span pitch plane transitions have to be cut, which adds labor, diminishes the floor’s appearance, and can introduce unsafe sharp edges, and large tile is simply less safe to stand on when wet. Using small ceramic tiles (or pebbles, or glass tile) avoids the issues large tiles present and, because of the combination of many tiles and grout lines, provides a more “grippy” surface—better for maintaining balance and traction when wet.

Yes.

Absolutely level! The planes of a Tuff-Form offer plenty of pitch to speed water to the drain, but every degree that’s lost to an out-of-level installation affects the drainage performance of a shower.

The perimeter of each Tuff-Form has a 1-1/2”-wide flat area for resting a level. If you have cut away a flat area, use the crest of the edge to set a level.

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Setting the Tuff-Form on the joists requires care and is the most critical portion of the installation. The entire perimeter of the Tuff-Form must have continuous support, so 2” x 4” blocking is required under edges unsupported by a joist. Additionally, the drain area requires support using two 2” x 4”s, one on each side, no closer to the drain hole than 6”. If you cut a Tuff-Form to fit around something, like the end of a wall, you must support the edges of the notched area. A Tuff-form must be level. This may require shimming or shaving joists to ensure flatness and a level installation.

Sure, if properly installed, a Tuff-Form makes a great dog-washing platform. You could also use a Tuff-Form for outdoor showers at beachhouses, the bottom of custom-made sinks or vats, basement drains, and many other creative projects.

You have a couple of options. As always, we recommend installations that avoid a barrier or change of elevation between the shower and the surrounding floor. You can remove concrete to a depth of 1” in the area where the Tuff-Form will go. We do this with a special concrete-cutting saw and blade (item code ARC555), first cutting along an outline of the Tuff-Form’s installed position, then making scoring cuts about 1” apart inside the perimeter cuts. We remove the remaining waste with an electric hammer drill and chisel. You can use construction adhesive or thinset mortar to install the Tuff-Form in the recess. Alternatively, you can install the Tuff-Form on top of the concrete and build up the surrounding floor to end up with a level entry to the shower.

A widely held misconception is that concrete is waterproof. In fact, concrete acts much like a sponge, absorbing and holding onto water over time. In a shower, water gets into the concrete by soaking through grout (tile may be impervious to water, but grout isn’t), leaking around the edges of the base, or seeping into cracks in the concrete that develop as the material ages. Many showers were made using a vinyl liner under a poured concrete bed, with a custom pitched surface for drainage. Unfortunately, over time water often collected between the concrete and the vinyl liner, creating a filthy, mold-ridden mess. Eventually the concrete crumbled, and these showers became unusable. Thousands of them are being removed from homes, hospitals, and other facilities every year. Installing an ARC Wet Room System on concrete provides an impervious surface, covers any cracks that may occur in the concrete, eliminates any potential for mold and mildew, and delivers consistent, precisely-controlled pitch planes for perfect drainage performance and predictable tiling results.

Chances are, the blocking you installed to support the drain hole is too close to the opening. If you look at the underside of a T-F you’ll see that there is a ring around the drain opening that’s higher than the ribbing. The Tuff-Form is designed so the ribbing rests on the joists and blocking. If the ring rests on the blocking, a high spot will result as screws are driven around the perimeter of the former. This error must be corrected before tiling the shower; if not corrected, the grout will crack, tile may pop, and water may run away from the drain. Besides failing to level the joists and blocking properly, this is the most common installation mistake.

If you are installing a Tuff-Form on a subfloor and there is a gap between the subfloor and the shower base, use pancake-size dollops of thinset mortar to bridge the gaps and provide rigid support for the base.

Yes, but do it carefully. Nothing bonds to cured silicone, so if any is exposed in places you intend to apply waterproofing, you’ll end up with a problem—be sure no silicone is squeezed into areas that need to be waterproofed. For filling gaps prior to applying waterproofing, like the Tuff-Form to joint junctions, use acrylic (butyl) caulk.

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Not a good idea. You’ll have to contend with two drains, and two drainage areas with a ridge in the middle that may hinder water flow. And the shower will be difficult to use for someone in a shower chair or someone who is unsteady on their feet. You’re better off using one base and building around it with materials like Permabase or Hardiboard pitched at the same angles as the pitch planes of the Tuff-Form.

All Tuff-Forms are made with an off-center drain hole. This helps position the drain hole to avoid obstacles that interfere with the drain installation. For example, when you set the Tuff-Form into position the drain hole may sit directly over a joist, but by turning the Tuff-Form you can avoid this conflict. A rectangular Tuff-Form offers two placement positions, while a square Tuff-Form offers four placement positions.

For some projects you’ll be able to trim an oversized Tuff-Form so that the drain hole is positioned exactly where you need it.

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