The Deck Building Ledger

The Secret to Successful Deck Construction

The Deck Building Ledger holds all the secrets to successful deck construction because it is the essential piece of wood that connects your deck to your home.

If you are planning to build an attached deck - this should be the first piece of lumber you carefully place and from which all other measurements are taken.

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The wood for your deck building ledger should be strong, straight and true. 

Choose the piece of lumber for your ledger very carefully, hold it up and look down the side of the wood to check for irregularities like warping and twisting.

Choosing your Lumber

The ideal deck building ledger should be free of ingrown knots and flaws, or at least have only very small knots.

The best flat board to pick out for the prestigious job of becoming a ledger is a vertical grain board - this is the wood which comes from the center of the tree and will show the center circles.

Boards with an arc grain, known as a flat grain board, are from the outer sides of the tree and are more prone to warping or cupping over time.

If you are building a top quality deck made out of only redwood or cedar then this doesn't apply to you, but otherwise, please make sure that you are only using pressure treated lumber.

Many people who opt for a more expensive option in lumber still use regular pressure treated wood for the deck building ledger and the joists because these are parts of the support of a deck that will not be visible.

If this is the case, remember to use the Redwood or Cedar for the outer joists and end beam, because although they form part of the under support frame they are visible when looking back at your deck from the garden.

Once you have selected and separated the best lumber you should have choice pieces for both your ledger and for your beams.

Positioning your Ledger

The first step in building a sucessful deck is finding the right height at which to secure your deck building ledger.

It is really important that you allow for a couple of inches step down onto your deck from your door, this is to help prevent rain water from running off the deck and into your home.

Remember also, in the final part of construction, your surface decking boards will be secured on top of the side surface of your ledger and joists, so:

  • Leave a 1" -- 2" drop from your door
  • Allow for the size of your decking boards - that will be another 2"
  • Measure 3" -- 4" down from your indoor floor level
  • And mark the wall showing the highest point of the ledger

A spirit level and a pencil are your next best friends, you shouldn't try to place a deck building ledger without one.

Measure and mark along the wall, the full horizontal length of exactly where you are going to place your ledger.

Fitting your Deck Building Ledger

If you house is covered in siding you have to cut out the exact size to insert the deck building ledger AND enough at the sides to also insert the outer joists.

Flashing should be inserted up under the siding and onto the top of the ledger, the join should be closed with sealant.

If you home doesn't have siding you don't need to use flashing but you should use sealant to close any gap between the ledger and the wall.

Four inch lag screws will secure your ledger into the wall and give you a level and firm foundation to build your deck design onto.

Attaching a Ledger to Siding

If your house is covered in siding you shouldn't try to attach your ledger to it -- for one thing it will never sit vertically straight and for another your lag screws won't penetrate far enough into the wall to get a fair grip and apart from that your drilled holes into the siding will allow water to enter and put your whole house in jeopardy 

The only way to attach a ledger successfully to a home covered in siding is to actually use a circular saw and carefully cut a pre-measured piece of the siding out, to fit both the full length of the ledger and the thickness of your outer joists -- on both sides.

The secret to success here is to cut a piece of galvanised flashing the full length of the new space you have cut out. I like to cut flashing to about 4"+ broad to give me plenty of flashing to tuck up under the siding and still have more than enough to sit on top of the deck building ledger to make sure that any water always rolls off away from the house (instead of going down inside the lower siding and concrete of the house.)

Use sealant at the top and sides of the flashing where it meets the siding to make the connection water tight.

Attaching a Ledger to a brick and mortar wall

If you don't have siding -- it's pretty straight forward, simply mark out the correct position on the wall using a spirit level and the actual lumber to pencil around.

Pre-drill the holes in the lumber the right size for your lag screws and washers. Offer the ledger back up into the marked space and use the holes to mark through to the wall in the exact place.

Drill the holes in the wall where you marked so that you can push in all anchors (plugs) which should be big enough for the lag screws to firmly fit into.

Attach the ledger and seal between the lumber and the wall to make the join water tight.

Admire Your Work

YOu can now stand back and admire your Deck Building Ledger attached to your home -- if attached at the right level and perfectly horizontal -- you have the beginnings of a great deck design for your home and it all starts with your deck design ledger.


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