I am a novice, and i am trying to build a shed myself. I don't have any framing experience.

I purchased a miter saw, and a circular saw. The plans call for 2x8 floor joists with 3 inches shorter on the inner short boards. So i purchased two 2x8x10 boards, and two 2x8x12 boards, cutting the 2x8x10 3 inches shorter. First the boards arent exactly 10ft.. they are about 5/8 of an inch longer. Why is that?

Second i don't have a table for the miter saw so i figured id get by with a circular saw.. i see the framers who build houses by me pretty much use only that.. i cut one end to make sure it's straight.. as it wasn't perfect. Then i made my final cut.. well i had a guide board, and not too expierenced with a circular saw, it kept getting stuck because of the blade guard was s getting caught and not sliding up. What was i doing wrong here?

Finally i got the cut straight as i had to go in a little bit to correct the cut. Now the cut is about 1/8th too short. I stopped here because i need advice. These boards are $15 a piece.. can i still use this one? Does every cut have tp be perfect? Can it be a little off and still be fine?

Am i over doing it trying to use a guide board? I see the framers zipping ends off free handed.. and im wondering if i am trying to be too perfect. I don't want to assume anything and have the shed look like a teo year old built it.

Maybe i need to just get a miter saw table and stick with using that?

Please help give me some pointers on measurements to get my shed floor frame square. thank you!

4 Answers 4


Practice, practice, practice. Very few people are born with circular saw skills.

Your blade guard issues might be a crummy saw, or you might not be coming in flat and straight. Make sure it moves smoothly and clean/lube it, if needed.

Wood being oversize is just one of those things. As long as you don't get less than a 10', you should be happy.

Regarding the undersized by 1/8" bit, you could probably ignore it, or cut all the rest of your pieces to match. Chances are you won't notice it either way.

If a guide board is working for you to get square cuts, then keep doing that. Otherwise, see the above about practice. For what it's worth, a sharp blade won't try to wander like a dull blade will.

  • 1
    Yes, practice. I can cut down the center of a lead line without a guide after a few decades of practice. And use your second (middle) finger on the trigger. This gives you much more rotational control.
    – isherwood
    May 29, 2018 at 15:24

The best way I know to cut framing lumber square with a circular saw is to get one of these protractor saw guide devices. They are adjustable for cutting at any angle but are normally setup for making square cuts. I use a framing square to set the protractor to an accurate 90 degrees since the built in angle pointer is not always super accurate.

Saw Guide Protractor:

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Framing Square:

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Saw Guide Protrator In Use Making Angle Cut:

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Back in the day when dimensional lumber ( DM ) was categorized into sizes 2x4 2x6 etc they were actually the dimension of their name. Over the years for the sake of getting more saleable board feet from the same size tree lumber mills started to make the DM smaller then its name. I.E. Now a 2x4 is actually 1 1/2 x 3 1/2 ( i attribute it to greed but i am sure if there is a GOOD reason someone above my pay grade will correct me.)

A good way to make straight cuts on dimensional lumber is to use a speed square

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as a fence or straight edge to guide your circular saw. Watch this video form This Old House to learn more.

Once you get proficient with a circular saw you can cut very well by just making a straight line and free hand cutting on the line. I use my free hand to help guide the saw and keep it from moving side to side. Sometimes the guard will hang up, Clamp your piece to a work bench/table and then hold the guard in the up position until you get far enough into your cut that you can let it down without it getting caught.

Technically all your joist should be the same measurement, so that your rin joist that runs perpendicular to them and is what the joist are attached to is not a wavy line. If you are using joist hangers and it is just a shed you may decide that it is OK to use it and just shim the 1/8th gap, or your could cut all ofthe joist shorter to match but this will change all of your dimensions for your walls etc. Not a big deal if your wall etc are not standard dimensions and you are going to have to cut your wall plates, wall sheathing anyway.

It is a shed and a learning experience, have fun.

  • Thanks on the speed sqaure tip. I did actually see that being used on This Old House before, not sure why i didn't think of that! Thanks! Now, I do have a Miter saw, I was thinking of picking up the stand for it at Home Depot for $99.. The Miter saw I purchased has a lazer guide too. Would I be better off using the Miter saw for these cuts? These boards are 12ft long, I do have some plastic saw horses I purchased to support the long ends.
    – eaglei22
    May 29, 2018 at 14:00
  • The "good reason" is that lumber is now planed smooth (or "sanded on four sides" - S4S). It hasn't been acutal size since it was rough-sawn (though originally, planed lumber was just 3/8" undersize, but that was changed possibly to simplify the math).
    – isherwood
    May 29, 2018 at 15:22

It is refreshing that you are able to purchase lumber that it longer than the length described, even if it is only 5/8" more. All lumber that I can recall used to be sold that way. Only recently in the past years of big box stores is the lumber exactly 10' or 12' and so on. The purpose for this was if you cut a number of blocks from a piece and each saw cut removed 1/8" you could still come up with 4- 24" blocks from an 8' piece or something like that. Another reason, back in the day, the ends of the lumber from the sawmill were not all cut square, so it was needed to cut all ends to ensure squareness.

If I am picturing your use of your saw, you are right handed and the narrow side of the table of your saw is the side you are resting on the material to recut the ends of your material. The guard from this position of cutting is not shaped to automatically raise while cutting. Only the wider base of the circular saw allows this.

An 1/8" short is no big deal, for joists, there should be joist hangers involved which will take up any slack or slight shortness of cut. For that matter the shed could be made a bit smaller, it does not have to be 10'X 12", it could be 9'-11" X 11'-11" and work perfectly still.

As mentioned in another answer, practice makes perfect, but with a careful eye you can cut your framing. The trick I use to watch my cut line is to look through a small space from the short side of the saw base where the edge of the blade is visible. That way I can watch my cut and not get pounded by sawdust.

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