I would like to build a small, 24" high deck, for a new entry door to the house. I have the deck plans all laid out, and am in need of a 2x10 ledger board under the door to attach the deck to. Most of what I have read on attaching a ledger board, suggests using large carriage-bolts through the ledger board and rim joist, with a nut/washer on the back side. Unfortunately, this section of the house has a finished basement, and it would be quite difficult if not impossible to access the back side of the rim joist.

What other options do I have? Would some hefty lag-screws work?

  • 2
    Note that a finished space with drywall is not the same as "no interior access." Cut a 2' wide opening in the ceiling along the wall, do your work, and replace the drywall. There's no need to risk the structure of your home to avoid doing some drywall repair.
    – BMitch
    Dec 13, 2012 at 14:56
  • Certain building codes make you attach the deck to the house, found out recently when I started building a deck for a client
    – user14395
    Aug 6, 2013 at 19:27
  • @Cruz Can you elaborate? If a free-standing deck is properly built I don't see why it should be prevented by code.
    – Hank
    Aug 6, 2013 at 20:20
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    If you attach a ledger board to the house, you have to seal the top (and maybe the bottom) of it and put some kind of flashing over it to keep water from seeping inside the wall along the lag screws. Jun 7, 2015 at 2:38

5 Answers 5


Lag screws should be fine. If possible, have them go into the ends of the floor joists as well. You can probably see where they are from the outside by looking at where the nails are in the rim joist.

  • If using lag screws into the floor joists, would drilling pilot holes be a good idea to prevent the joists from splitting?
    – Niall C.
    Oct 18, 2010 at 17:27
  • 3
    I would explicitly avoid going into the ends of your joists. Even with pre-drilling, a ledger-sized lag screw (~1/2"?) would be very likely to split the end grain of a 2-by joist. Oct 18, 2010 at 18:48
  • @Niall - Yes, it would be. with lag screws, I would always drill a pilot hole regardless. Oct 19, 2010 at 16:14
  • @MikePowell Not only that, but what if you have engineered joists? You'd be trying to put a screw edge-on into a piece of thin oxboard. Jun 7, 2015 at 2:31

DANGER DANGER DANGER.... As we speak, I am replacing an entire 5 foot knee wall 20 feet long, jacking the floor joists, new studs, mold remediation, new sills, new top plates, new insulation, floor joist sisters, a very expensive 6 foot slider is in jeopardy. This fix is gonna cost my customer over $3,000 minimum Ants and rot everywhere, all the way to the concrete. Why you ask? The deck ledger was lag bolted to the the house through the vinyl siding!!!! no flashing or Grace ice and water shield under the door or around the ledger, not to speak about invading the water tite integrity of the siding itself. Water seeped in the wall for the last 10 years. everything in the wall was wet and mold was starting to show on the interior sheetrock. 24 inches is not high. Consider a plan where the deck is free standing and stands a 1/2 inch away from the building, and you will avoid all these potential problems. Seriously, if you don't know how to place a ledger and water proof it completely and then reinstall vinyl siding under the deck and adjacent to it etc., then seek a bit of professional advise or go to a self supporting deck. simple cross bracing will make a very stable deck not attached to house.

  • This is the better answer. At the very least, the accepted answer should have at the very least mentioned using some kind of resilient, flexible sealant along the top of the ledger board, and additionally putting some kind of flashing above the ledger board to deflect water away. But I like the freestanding deck better. Jun 7, 2015 at 2:35

Do yourself a favor. Yes, you can bolt things to the joists. Heavy lag bolts are probably ok. Through bolts are better, but if it is not an option, then you do what you can.

The issue is, if you do just bolt this to the wall of your house, use flashing. Keep the water from getting into your house.

By way of example, we have a deck on our house that wraps around part of the house. The person who did the deck just bolted a treated 2x10 to the wall, though the rim joists, right through the vertical cedar siding. Then they ran joists and a deck on top.

Of course, this creates a place for water to collect. The crevice collects leaves, acorns, small sticks, seeds, etc. That is a breeding ground for carpenter ants. Worse, the deck actually wicks water to the house. So I must go around twice a year with an air hose, blasting the junk out. Then I spray for ants. One day, I'll get tired of this and tear the deck surface off, adding proper flashing to prevent these problems.

Do the job right the first time.

  • Thanks for bringing that up woodchips. We'll definitely be properly flashing things. I need to be replacing the vinyl siding, so I'll strip the siding off, place some back flashing, attach the ledger, then flash over the top of the ledger.
    – MarkD
    Oct 18, 2010 at 17:01

Use these LedgerLOK fasteners. They're like lag screws but smaller diameter, and are engineered just for this purpose.

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    I can attest that these work really well as long as you're sure you're sinking the length of the fastener into something. Also invest in a decent impact driver if you're ever going to need to drive lag screws or similar fasteners. Sep 10, 2015 at 3:03

3/8" or 1/2" lag screws spaced to code specs. Definitely pre-drill a pilot hole of appropriate size. Also, try to at least fasten a metal drip edge between the top of your ledger board and the next piece of siding and then caulk it well with silicone.

And also take a good look at construction guidelines for attached decks because the bigger they are and the more they are deflected by walking or wind, the more force will be transfered into the framing of your home. I am not a builder but I've learned the hard way that energy only changes forms.

** p.s. - this is with the assumption you've taken off the hardboard siding or whatever is covering the framing you are attaching to, although I think that is covered. I simply added my voice to this conversation because I just did this same project very recently. **

  • 2
    Depending on your area, code might specify that you have to go into a stud or beam. That is, any structural load needs to be taken to the structure, not the cladding (bricks). Dec 12, 2012 at 22:08

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