How Much Extra Tile Do You Need? Baseboard? Insulation?

by Margaret · Published September 26, 2018 · Updated March 2, 2020

**Our honesty policy: This post may contain affiliate links and I may be compensated if you make a purchase at no extra cost to you. Some are, some aren't--I do some comparison shopping. The important thing is you will know exactly what we are talking about. Drop a note/comment if you have any questions on the products as these are materials and tools we use on our own projects.

Often times you hear numbers between ten and twenty percent when you ask how much extra tile do you need…or how much baseboard…or insulation…or how much lumber/mortar/anything!

Those numbers seem so huge. Is all that extra really necessary?

How is this for an answer we all hate: it depends.

Is this a DIY project? If so, you have some flexibility. Let’s take a couple different projects to explain.

Laminate Flooring

Check out this calculator if you are looking to see how much laminate flooring you will need for your project: Laminate Flooring Calculator – Box Count & Cost

We also discuss the details of overage after the calculator itself.

Installing new baseboard

As I discussed in minute detail in this post, you barely need any extra material when it comes to a DIY installation of baseboard trim. After running all those Google Sheet calculations for my entire house, I ordered the sticks and added one extra. Again, your own number depends on your confidence. I figured if I messed up on a longer piece I would use it as spare for any smaller pieces. I also felt confident I had enough margin of error for any of those fancy coped corners.

Tiling

The same plan could be used on a tiling project. However, you should definitely order more than just one extra tile–I’ve definitely had one travertine tile break apart in my hand just because the stone structure was not strong enough. I wouldn’t go so far as to suggest twenty percent, but how much you want is dependent on your comfort level.

At the same time, the extra material needed for a tile project also depends on your design. If you’re planning out a shower with marble tiles where the lines go in the same direction you are forced into using pieces that only go a certain direction.

How much extra tile do you need? If you're planning out a shower with marble tiles where the lines go in the same direction you are forced into using pieces that only go a certain direction. Notice how most of the tiles in my friend's stunning bathroom have the most of the marble lines meandering to the upper left.*

Notice how most of the tiles in my friend’s stunning bathroom have the most of the marble lines meandering to the upper left.*

You WILL have pieces of scrap that you simply cannot use. This is when you need to order more overage. There are still places you can use the extra, such as window sills, a shower nook, or other details. Instead, save these for window sills.

Similarly, if you are installing tiles diagonally there are infinitely more cuts around the exterior walls. While you can use scrap, there is only so much you can reuse. There will be more scrap than you would with a square design.

If you are installing tiles diagonally there are infinitely more cuts around the exterior walls. While you can use scrap, there is only so much you can reuse. There will be more scrap than you would with a square design. As you can see, if you choose a diagonal pattern, not only are you cutting many more tiles, but cutsa around corners are more difficult--cutting on a 45 degree angle is much more prone to error...and mulligans.

As you can see, if you choose a diagonal pattern, not only are you cutting many more tiles, but cuts around corners are more difficult–cutting on a 45 degree angle is much more prone to error…and mulligans.

The intent is not to discourage this design choice, but be aware of the extra tiles necessary. There are certainly some strong arguments for choosing a diagonal layout…in a later post.

Insulation

Another area for planning efficient use of materials is insulation. The basics are simple. Answer these questions:

What kind of space is being insulated?
What are the material sizes and spacing (2”x4” studs spaced 16” on center or 2”x6” studs 16”/ 24” on center, etc.?
What R-value is needed?
Indoor?
Outdoor?
Vented space?
Added soundproofing and/or fire resistance?

he answers to these questions will help to determine your product choices. Once you choose the exact type and brand you’ll know how much square footage comes in a single batt of insulation. Other things you should be aware of is how the insulating material will be installed, paper-facing, or not.

The basic quantity estimation comes from square footage calculations and comparison to the product yield. For this example, I will refer to a current project using Rockwool insulation (Roxsul for those of you familiar with Mike Holmes). We have two walls that are 11’x8’, 2”x4” studs framed 16” on center and one wall 15’x8’ with the same construction. Total square footage to insulate: 296 sq. ft. Rockwool R15 for 2”x4” stud bays 16” on center covers 59.7 square feet per bag. 296/59.6 = 4.958 bags→ round up to 5 bags. Five bags is the minimum purchase in this example because you may have strange cavities or your framing may not be perfectly distributed. The purchase of the additional bag acts as an insurance and time saver versus returning for another supply trip.

You might be saying, “Hey wait, what about the windows?!? Those obviously don’t have insulation. Why not subtract those out?” Most manufacture suggestions use windows as fudge factor. You can use it to fill the the gaps and unexpected places. Or, because you are here on this blog, subtract it out if you feel mathematically inclined.

An argument for more

Tradesmen who are paid by the job are quick to return your home back to you and move on to the next expectant customer. They minimize waste from their experience, but they do not have the capacity to sit there and create an Excel spreadsheet to fully minimize waste. This is especially true when labor cost is more than the material cost. They will need more baseboard, tile or whatever the project entails.

When you’re doing the work yourself you can sit there and take the extra time to calculate how to best use each piece of tile, baseboard, or lumber so that you’re using as much of every piece as possible. However, even if this is a DIY project you don’t want to be running back to the store for one more baseboard/tile/etc.

There are other times when you need extra for the future. A cracked tile is not easily replaced after the manufacturer discontinues the style. Even if they don’t there could be a difference in color between lots.

This is why we stashed extra porcelain, travertine, granite tiles along with other extras in the attic.

A possible solution if you do go overboard

If all else fails, order more and know the store return policy before you place your order.

If it is a special order item, is it even returnable?
Can you return a individual tiles or will they only take back unopened boxes?
How long is their return window?

Try to buy the materials as close to when you are beginning your project as possible. So when you are done you can legitimately return what you can within the store’s return window.

Otherwise you have to store it–probably in your garage. No one wants that. We need more room for power tools!

*If you love the photo of this bathroom, need to sell your house, and live in the Phoenix metro area, consider Ryan Nemec for your photographing needs.