How Thick is a Plumbing Wall?

Everyone knows that once you open up the walls of a home, quite a few things may be discovered. Sometimes it’s damage with the wood inside the walls of the house that couldn’t be seen before or electrical wire problems, and sometimes it’s plumbing problems.

In older homes, a problem that is found pretty often is that the plumbing walls in the home are not thick enough. And when trying to do some home improvements on your own, questions about the plumbing wall quickly come up. The big question is, how thick is a plumbing wall supposed to be?

How thick is a plumbing wall?Pin

The standard thickness for plumbing walls is 6 inches. With plastic pipes, you can get away with the walls being 4 inches thick instead. The thickness of the plumbing wall does depend on the types of pipes in your home. Metal pipes, which are very common pipes to find in older homes, are larger in size. Because of this, they require more space inside the walls, which is why they need 6 inches of space.

Plastic pipes, or PVC pipes, are smaller in size, therefore they need less space. These pipes, which are being used more and more in newer homes, only need 4 inches of space. For more information on the reasons behind this, and to learn more about plumbing walls, keep reading!

Plumbing Wall Information

Plumbing walls, which are also known as wet walls, are just that. They are walls that have plumbing on the other side of them. It’s really that simple of an explanation. Plumbing walls are the walls behind the kitchen sink, the bathroom room sink, the toilet, and the shower. All of these places have pipes running through the walls that make these plumbing walls essential. Here’s a diagram for an idea of what plumbing in a whole house might look like.

Plumbing wallsPin

What makes plumbing walls so essential? The structure inside the plumbing walls is made stronger and thicker to accommodate the pipes and to help ensure the structural security of the house remains intact. In other words, they are made to be stronger and thicker to help keep the house and the pipes themselves safe.

Plumbing walls are also designed to withstand moisture build-up. This helps prevent mold from growing inside the walls of your home. It’s also why plumbing walls are used instead of normal walls that will be found around the rest of the house. Plumbing walls are only put where they need to be, which is anywhere that has pipes in the walls.

Plumbing Wall Thickness

As mentioned above, the standard thickness of plumbing walls is 6 inches. This is achieved by using 2X6 studs. For those that may not know what a stud is, studs are pieces of wood inside the walls that help frame and support the house. One reason that 2X6 studs are used for plumbing walls is that they are very strong.

For the pipes to be able to get to where they need to go, sometimes they have to go through the studs. Although it’s not ideal, sometimes there is no other way around it. For this to happen, holes must be made through the studs so that the pipes are able to get through. 2X6 studs are able to support the weight of the house and the added weight of the pipes easily.

2X6s are 2 inches in thickness and 6 inches in width. This means that there are 6 inches of space between the exterior walls of the home and the interior walls of the home. There are lots of things that go in this space, like the air ducts, electrical wires, and plumbing. When there is plumbing involved, the walls have to be thicker to accommodate the size of the pipes, which is why 2X6s are used. It leaves plenty of room for the pipes inside the walls.

Sometimes the rest of the house will have a smaller space in between the exterior and interior walls and just the plumbing walls will have the 6 inches of space here. However, it’s pretty standard for 2X6 studs to be used for framing the entire house and not just the plumbing walls. This means that the 6 inches of space between walls will be present throughout the house and not just for the plumbing walls. This will all depend on how old the house is though.

Plastic Pipes

Plastic pipes, or PVC pipes, are a little bit different than other pipes. One of the big ways that they differ is in their size. Plastic pipes are much thinner than metal pipes, and this is referring to all types of metal, not just one. They are much smaller, easier to install, and easier to fix than metal pipes. Because of this, they are getting used more and more for plumbing, especially in newer builds. They do connect to the main sewer line, which is a metal pipe, but in the walls of the house, they would be plastic.

PVC pipePin

The size of PVC pipes presents a huge difference to metal pipes, which makes the amount of space that they need within the walls of the home change to a lower amount. When plastic pipes are used, the plumbing wall can be 4 inches thick. If the plumbing walls are only 4 inches thick, 2X4s are used in the wall instead of the 2X6s. This means that instead of the 6 inches of space that the 2X6 studs give between the exterior and interior walls, there are only 4 inches of space. And everything fits and works perfectly fine since the plastic pipes are so much smaller in size than metal pipes.

The electrical wires and air ducts aren’t affected in any way with only having 4 inches of space since the extra two inches are only because metal pipes need that space. 2X4s are also strong as well, so the strength of the frame of the house isn’t something that needs to be worried about, they just provide less space in the walls of the home. But the plastic pipes don’t need that much space, which is why they fit perfectly in that 4 inches of space.

Scroll to Top