Diagonal Tile Planning in SketchUp

Matt Donley Sketchup Tutorials Leave a Comment

If you are installing floor tile, you need to carefully plan the layout so you know where all of your cut pieces are going to land. You don’t want to just randomly start at one wall, only to find that you need to install a 1/2″ sliver of tile once you get to the other side. SketchUp is a great tool for visualizing and planning complicated floor tile, to ensure cut pieces are sized well. You can also get an accurate material count, including accountability for tiles that will be used from cutoffs of others.

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In my interview on the SketchUp Talk podcast, Aaron asked me what was my “most meaningful model?” I replied that I find the most meaningful models are the ones no one else sees. They are models that serve a specific purpose to help me solve a problem in my mind, they don’t necessarily look pretty, but they are incredibly valuable. We’re going to bend a few rules in this model, but I think you’ll find this approach extremely helpful in planning a complex tile project.

What’s So Hard About Tile?

The easiest tile layout is when you have a square room with 4 walls, and are installing square tiles. But even so, you can’t just start tiling from one corner of the room, and hope everything works out fine.

Most times, it’s better to measure to the center of each wall, and either align the edge of a row of tile with that center-line, or center a row of tiles directly on the center-line. It all depends on what kind of cut piece you end up with at the walls, doors, and whatever other obstructions exist in the room. If you can center tile like this, it creates a nice symmetry in the room which is visually pleasing.

Irregular Tile Shapes

Square tiles are easy to plan because all of the edges of the tiles align. You only have two grout line intervals to worry about (One along the “X” axis, another along the “Y” axis.) When you have an irregularly shaped tile, like 6″x24″, the grout lines stagger, creating an additional grout line interval that staggers with every other row.

Irregular Room Shapes

If a room isn’t a simple 4 wall square, things get even more tricky. Here is my bathroom that I am installing tile in:

You might be dealing with walls that are not parallel or square. There may be doorways or other transitions that you have to navigate. A bump-out in the wall might cause a small change in wall projection that can make it harder to offset the tile joint. A diagonal wall can create additional chances for an unacceptable small cut tile to occur.

When you actually count up the number of wall projections that occur in this room, there are 15 different wall surfaces that need to be coordinated with 3 different grout lines in order to make sure the tile looks aesthetically pleasing , while also avoiding small pieces of cut tile.

Diagonal Tile Layout

I decided to install the tile diagonally. Although I was initially drawn to the idea because I thought it would work well with the oddly positioned doorway into the bathroom, I have to admit that the main reason was simply because I had no easy way to cut 24″ tile.

If the tile was installed parallel to the walls, I’d inevitably need to cut some tiles along the 24″ side.

There was a single wall that was angled on a 45°, so in order for this to work, I’d have to start the tile layout against this wall, and hope that the tile would land nicely as it ran into the corners, and I wouldn’t get left with a small piece that I’d have to install anywhere.

With tile installed diagonally, you don’t have to worry about any individual tile edge alignment, but instead, every single intersection with a wall becomes an opportunity for a small tile cut. I was also worried about how the tile would end up at the bathroom entrance, where it would transition from tile to wood. I definitely don’t want a small piece there.

Here’s what my final layout looked like:

Let’s take a look at exactly how I used SketchUp to help me plan the floor tile in my bathroom, so you can use SketchUp for your own project.

Measuring the Floor for SketchUp

For a project like this, you want to aim to have measurements accurate to within 1/4″ or so. The baseboard will cover 1/2″ of the tile against the wall, but the tile should be held back from the wall by a 1/4″ for expansion. More importantly, you need to account for the squareness of the walls. No house is perfect, and old houses are definitely not perfect. So you need to establish some reference lines, then measure off of those to create some measurement lines for where your walls are.

So the first step is to snap a chalk line on the floor, positioned somewhere in the middle of the room, along the longest span in the room. (It isn’t important to consider where the tile will be positioned yet, these references lines are for the walls, not the tile.) You want the line to be as parallel as possible to the wall you are measuring from, but no doubt, there will likely be some differences +- 1/4″. That’s ok, those differences will be recorded and captured in the model. For now, you just need to establish a “true” straight reference line.

Next, you need to establish a second straight line, that is exactly 90° to the first line you created. You can do this using several methods. The level of accuracy achieved here will determine how accurate your model is, so try to get it within 1/8″. I had a 48″ T-square (for drywall), which I used to mark two points on the floor, then I was able to reference those two points when I extended my chalk line over them, so I could snap a chalk line spanning the entire room. You can check squareness using the Pythagorean theorem.

Once you have the two crossing chalk lines established, you can now start taking measurements along the walls to the chalk lines at all corners and at regular intervals (If you feel like your walls are bowed.) For instance, instead of measuring only the start and end of a wall, you can also measure every 2′ of the wall, and record each dimension as you go.

You should measure from both lines, for each point along the wall you want to pin. This will give you an [X,Y] coordinate that you will be able to use once you get to SketchUp. It’s important to measure back to the chalk line for every dimension, as this will ensure that you are always referencing from the same plane in all of your measurements.

Here’s what the final measurements should look like: (Note: I missed a few measurements on the doors and the toilet position.)

Importing Walls into SketchUp

Once you have your walls measured, open up SketchUp. Start by creating a large rectangle with the RectangleR tool, much larger than the scope of your project, Triple-click it > Make Group that way you can draw on top of it without having anything stick to it. This rectangle is just a reference to help the SketchUp inference engine infer that we want to draw along a single plane.

Next, draw the two reference lines that you snapped on the floor using the LineL tool. Since it’s important that these lines do not accidentally get shifted, you should triple-click these lines to select them all > Right-Click > Make Group. Then Right-click again > Lock.

At this point, you can pick a wall to start with, and use the LineT tool to create a guide at each interval you measured from the first chalk line.

Next, using the LineT tool again, start at the intersection between one of the guides you just created, and the second chalk line in the model. Click to start a guide point. Click again to place the guide point, then type in the dimension it should be at and press ENTER.

Once you’ve added guide points for all of the measured points along a single wall, use the Eraserc tool to erase the guide lines, (But make sure to leave the guide points behind, you’ll need those.) You want to erase the guide lines before continuing to the next wall so you don’t get confused about which guide lines represent what.

TIP: When you create a guide point along an existing edge or guideline, the new guide point will not have a connecting guiding tail. If the guide point exists in a new point in space, a guide tail will exist between the start and end point of the guide point.

Once you have completed creating all of your guide points, you should be left with your two reference lines, and a bunch of guide points. Drag a selection box around the guide points, group them, then lock them. All that’s left to do is use the LineL tool to connect the dots to create your wall outline.

Be extra careful when you are trying to snap to guide points that are very close to being parallel to an axis, because the axis inference may be “stronger” then the guide point inference. You might need to zoom in further to the guide point in order to accurately snap.

When you’ve completed your wall outline, Triple-click click the wall line segment > Right-click > Make Group.

If you want to, (depending on how accurate you are trying to be), you can use the [SUP_offset] tool to offset the walls by whatever gap you plan to leave between the tiles and the wall.

You can now delete the reference rectangle you created at the beginning of this tutorial.

Spacing Tile in SketchUp

With the walls established, the tile can now be laid out. It might be tempting to simply take whatever measurement is on the box of tiles, and add the dimension indicated on the bag of tile spacers you have, but this would not be very accurate.

Instead, take 5 tiles out of the box, and line them all up, using spacers in between each tile, to get an accurate measurement of the span of 5 tiles in a row. This will greatly increase the accuracy of your tile mockup in SketchUp.

These are actually the shower tiles. I forgot to take a picture of me measuring out a span of floor tiles. But you get the idea.

Measure the width and length of several of the tiles, and try to identify the average measurements. Use the RectangleR tool to create a rectangle that represents a single tile. Triple-click > press G to turn it into a component.

Next, use the LineT tool to create a guide matching the overall distance of 5 spaced tiles. Then, grab the MoveM tool, snap to one of the top corners of the tile, click to start, tap CTRL to toggle “Copy” mode, and snap the copy to the guide you just created. Then, type in /4 ENTER to create 4 copies of the tile, spaced evenly by the spacer size. (Keep in mind, the actual space between each tile may not match the spacer size because you’ve measured an average over 5 tiles.)

TIP: Z-Fighting occurs when there are two faces overlapping along the same plane. Since we are drawing on top of a larger reference rectangle, each tile is Z-fighting with the rectangle. To alleviate this effect, go to View > Face Style > X-Ray.

At this point, it’s a good idea to select the 5 copies of the tiles (hold CTRL with the Select tool to select multiple) and right-click > Make Group, so that you’ll be able to manipulate the position and rotation of all of the tiles.

Once you’ve grouped the tiles, use the MoveM tool to grab one of the rotation handles and rotate the group 45°. This will help us identify how many additional copies we’ll need to span the entire floor.

To continue the layout out the tiles, use the Select tool to Double-click on the tile parent group to jump back inside of it. (Notice how the axes in the group remains aligned to the tiles, even though we rotated the group? This is one of the reasons we created the group before rotating the tiles. We wanted to keep the axes aligned with the tiles. You can always re-orient axes using the [SUP-axes] tool, this is just easier.)

This particular tile floor is going to be laid out so every other joint is staggered. So we need to align the center of the grout joint of one row with the center of the tile on another row. Offsetting the tile perimeter by the thickness of the grout line will help us set the spacing for the rest of the tiles.

Inside the parent tile group, Double-click on one of the tiles, then use the [SUP_offset] tool to offset a rectangle, snapping to an adjacent tile. This offset rectangle represents the entire grout line spacing that should exist around every tile. These edges do overlap adjacent tiles, and that’s ok, we’re just using it for reference. You can delete the face if you want, or apply a different color to represent the grout.

In order to align the center of the grout space to the center of a tile, we need to add a small line segment with the LineL tool, spanning the entire width of the grout joint, so that we can snap to the midpoint of that line.

Exit the tile component, then select all of the tiles with the Select tool . Activate the MoveM tool, zoom into the small line segment you just created, snap to the midpoint, click to start the move. Snap your mouse to the midpoint inference of the tile in the next row. Click to finish the move.

Select all of the tiles again, and repeat the process of copying the tiles until you’ve covered the entire floor area. Make sure you copy plenty of tiles that extend well beyond the wall boundaries. You’ll be adjusting the positioning of the tiles and deleting extra once you’ve finalized the position.

Analyzing Tile Position

With all the tiles laid out, exit the parent tile group so you can move it around the floor as a single entity.

In my specific situation, I wanted to try and get away without having to make any long cuts on any of the tiles, so I started by having the tiles aligned with the small angled wall in the bathroom, considering a 1/4″ air space. From there, I just initiated a move and locked it along the axis parallel to that wall by hovering over it and tapping the DOWN arrow.

Then I just slowly moved my mouse while looking at each wall intersection and especially the bathroom door entrance and where any wall corners occurred. Keep in mind where the vanity is going, so you don’t have to worry too much about how that looks. The toilet cutout was also a consideration, however, since most of the toilet covers immediately next to the flange, this is less of an issue.

Once I found a position I liked, I clicked to lock it in place. I then checked everything again more carefully.

Go around the wall perimeter and delete each tile that entirely exists outside the boundaries of the walls. You can use the Eraserc tool, or select them and tap DELETE.

Takeoff material list

You can get immediate feedback on the number of tiles you need by clicking on one of them and looking at the Entity Info window (Window >Default Tray > Entity Info). It will tell you how many copies of the selected component exist in the model.

Of course this isn’t entirely accurate, because you’ll be able to use cutoffs from one tile on the other side of the room. In my situation, I was comfortable enough adding 10% to this number and purchasing my materials knowing I’ll have plenty of extra (which I did), and I ended up returning one tile short of a full box of tiles to Lowes.

For estimating thin-set mortar coverage, you can just select the face inside the group representing your walls, and Entity Info will tell you the area.

TIP: If Entity Info is showing you square inches, instead of square feet, make sure Window > Model Info > Units > is either Architectural, Engineering Feet, or Decimal Feet.

However, if you wanted to identify where you plan to use cutoffs, I would recommend doing it like this:

Accounting for cutoffs

To account for tile cutoffs, you need to choose a tile that you’d like to use the cutoff from, Right-click > Make Unique. (You don’t want to mess up all the other full tiles in the model.)

  1. Double-Click on the unique component with the Select tool to open it.
  2. Use the LineL tool to trace over the intersection of the wall on the tile. You should now have two faces on top of the tile.
  3. Use the Paint BucketB tool to apply a red color to the part of the tile that will be cut off.
  4. Select the face that represents the cutoff, tap CTRL+C to copy the face. Press CTRL+V to paste the face to your mouse cursor. (Note, you should still be inside of the tile component.)
  5. Look around the floor to find a full tile that could be replaced by this cutoff piece. When you’ve found one, click to place the face, and reposition it as needed to align properly.
  6. Exit the component, then delete the full tile that you just replaced.

I like this approach because you could still quickly get a count of the number of tiles (even though we now have unique components) by entering the parent tile group and dragging a selection box over all the tiles. But you also get the visual reference of which tiles are being cut off, and you have a direct relationship between the cut tile, and where the cutoff piece is being used because the cutoff face exists within the same component as the main tile.

So in this example I need exactly 64 tiles. But this assumes the following:

  1. I cut every tile accurately
  2. I don’t break any tiles accidentally
  3. I use the tile cut offs in the exact positions I have planned to use them in SketchUp.

I actually didn’t plan this far into my tile project, and just got extra tiles and used cutoffs as I assessed them while installing the tile. But this just demonstrates that it is possible, and could be worth doing on large projects where you have many rooms that need to be tiled the same way, like in a multi-unit project where several apartment units repeat throughout the whole project. Small increases in efficiency and accuracy lead to greater savings.

Planning Tile Installation

When it came to actually installing the tile, I didn’t actually cut all the tile pieces according to what I planned and measured in SketchUp. I’m not that crazy! lol. There are always small adjustments “in the field” that happen incrementally that cause dimensions to be off a little bit. H

Instead, what I did is I used the model to help me figure out where to snap lines on the floor to align the tiles during installation. I needed a single, long line to establish the long direction of the tile, and two lines perpendicular to that to align the staggered joints.

To do this, you’d find where you want that line to be while looking at your model, then you’d measure along your original reference line until you intersect with that row of tile. Take that measurement and transfer it to the floor. Mark the same distance along the other reference line. Now, you can snap a chalk line between these two points and it will represent your starting row, which will be 45° from your reference lines.

You’ll also want to create a set of lines to reference for the grout joints along the other direction. Since these tiles are staggered, we’ll need a set of two parallel lines. (Use the “3-4-5” Pythagorean theorem to align.)

Check your layout! You’ll definitely want to double check everything and measure a few different points in the room and check it to the model, to make sure you haven’t made a mistake.

Installing the Tile

I ended up doing a rough layout and pre-cut all of my tile before mixing any thin-set. I then put blue tape on each of the cut tiles and numbered them, and wrote a corresponding number on the wall (which will be covered with baseboard) so I knew where to match up the tile.

Due to all this careful planning, I was able to install the tile floor well within 1/4″ precision to what I had planned in the SketchUp model. This would have been very challenging to plan in the field, but SketchUp made it very easy.

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