20 Nov. 2011|
Wood deck lag bolts,stanley 212 scraper plane,building custom office desk,full size platform storage bed plans - PDF Review
In our photo the 6x6 post was notched to leave a thick component that could be through-bolted (or lag bolted) to the girder.
A look at the other side of the deck girder (beam) above shows that the builder must have been short on nails.
When drilling holes through a scab or other framing member, and if multiple bolts are to be installed (red circles on the scab in the photo at above left), I [DJF] like to stagger the bolt hole positions in order to assure that no two bolts run through the same vertical grain in the wood. That's the strongest connection as it reduces the chances of splitting of the wood between two holes drilled in the same grain section of the lumber. You'll also notice that we don't place the bolts too close to the end of the scab nor too close to the top or bottom edge of the girder nor too close to the top of the post - locations where splitting may be more likely.
The two 2x10's comprising the deck girder in our photo above have not been bolted together.
Our photo (above left) shows a typical steel joist hanger used to speed and aid the construction of a deck. When the fasteners corrode, they contribute to decay in the surrounding wood, further weakening the connection.
Use of toe-nailing, or angled opposed framing nails (Double-Shear in Simpson Strong-Tie's patented joist hanger such as the item adapted above), can permit the use of fewer total nails in a wood frame construction.
Often by using a coarse-thread self-tapping construction screw you can pull back decking or framing into position.
I' trying to find a double 2 by 10 joist hanger that I can secure to a metal post that is strong enough for an inside deck. Whenever you read a story, or watch a news report on deck failure, the cause is almost always due to how the deck was attached to the house.
Prior to 2003 all pressure treated decks were treated with a chemical called: Chromated Copper Arsenate (CCA). This entry was posted in Deck Fasteners, Decking Installation, Decking Maintenance on January 31, 2013 by Ms. The solution was to reassemble the deck using more consuction screws, and once it was back in place, to reenforce those screws with through bolts and lag bolts large enough to contain the seasonal stresses. To ensure that our humid winters and dry summers don't cause the structure to pull itself apart, each of the main 2x6's needed to be reenforced with a lag bolt, but unlike the lags shown above standing "proud" of the board, these needed to be recessessed so that their heads didn't get in the way of the siding that be attached to those 2x6's.
As Windward evolves, we are steadily learning about techniques that meet our long term needs, lessons often learned amidst the frustration of rebuilding something, like that deck, that didn't work out well enough. Because the siding will be attached to the face of the 2x6, the first thing that needs doing is that we need to drill a hole into the 2x6 to accept both the head of the lag screw and the washer that enables the lag to get a grip on the 2x6. A flat-blade drill leaves a nice tapered hole in the center of the hollowed out space, and that hole would make a nice starting hole for a lag bolt. Here's a pic showing a bolt (on the right) that sheared off at the weak part where the threads start.
When doing a couple of bolts, there's no problem with just using a small wrench to ensure that one's mind doesn't wander and let habit‒and muscle memorty‒take over.
On a job like this, there are a couple of tricks that will help prevent the aggravation of having bolts shear away.
Another trick when using a large ratchet to drive a small bolt is to only use a couple of fingers on the handle instead of a full grip. Another trick is to use a ratchet that's no larger than the diameter of the lag you're driving. The damaged, over-nailed wood framing shown in our photo is discussed at TOE NAILED FRAMING CONNECTIONS. Also see Deck Nails, Screws, Hidden Fasteners and see New Preservatives and Corrosion where we describe structural fasteners designed for use in pressure-treated lumber. Also see DECK COLLAPSE Case Study (collapse of a new code-approved deck) and DECK FLASHING LEAKS, ROT Case Study for an example of an older deck with rot and collapse due to improper construction and missing building flashing.
At Fasteners, Nails, Screws, Hidden, for Decks we discuss choosing the proper nail, screw, or hidden fastener for fastening deck boards, railings, or joist hangers.
If you select the proper depth of joist hanger to match the depth of the deck joists, the manufacturer is giving you a clue about the number of nails required to make a safe and secure connection - every hole in the hanger gets a nail. Our photo (above left) illustrates use of a lag bolt to connect the deck ledger to the building structure by bolting to the rim joist. In time, we scrapped out that deck, but while its gone physically, the memory of that failure influences how we build today.
If you look closely, you can see the heads of the two construction screws (one above and to the left of the top lag, and another below and to the right of the bottom lag) that initially held the board in place before the final installation of the lag bolts.
Without the washer, the head of the lag would just dig into the wood instead of compressing it, thereby greatly lessening the strength of the bond between the 2x6 and the 4x4.
Unfortunately, given the length of the lag screw we're needing to use, the amount of force needed to screw it all the way into the 4x4 would be such that the lag would be likely to fail. This sort of work offers a good deal of satisfaction but it can be quite frustrating to over torque a bolt and have it snap off. One situation in which this can happen is when one is unknowingly trying to screw a lag into a knot that's being hidden by the 2x6. And at Fasteners, Nails, Screws, Hidden, for Decks we include examples of fasteners that should not be used in joist hangers, such as drywall screws and other non-structural screws. When pressure treated lumber comes in contact with galvanized hardware, the chemicals eat through the hardware, causing the hardware to corrode, and the deck to fail.
Snapping off a bolt in something like an engine block is such a pain that mechanics often use different ratchets depending on whether they're taking something apart, or putting something back together again. Everflashing produces a variety of specialty flashing products including flashings for use with decks at deck ledgers and deck perimeters. Over time, these fasteners are known to corrode, which in turn deteriorate the wood, or the wood expands and contracts around the nail causing the nail to literally slip out without notice.
So every time you come into contact with your pressure treated deck, you are making yourself vulnerable to the dangers of arsenic. It was exposed to the weather, with the result that the wood it was constructed out of swelled with the wetness of winter, and shrank in the dryness of late summer. If the timber, or in this case the 2x6, splits, then almost all of its strength is lost; the more relish, the less likely the wood is to split.