Garden deck

Ledger:

• Attach ledger (e.g. pressure treated 2 x 10) to exterior of house, anchoring to existing foundation using concrete anchor bolts. You can use epoxy filler if foundation crumbles on drilling (e.g. weak mortar).
• Place small vinyl spacers (e.g. 1/4 inch, 1/2 inch) between foundation and ledger, so that any water running along exterior wall will drain past ledger, instead of accumulating on it.
• The level of the deck surface should be lower than the level of the door (e.g. 6 inches), so that snow falling on deck won't fall back into house.
• Rationale on using a ledger as opposed to piers to support deck on house side: fill dirt after mold remediation will likely leave unstable soil around perimeter of house, so piers might settle if you built piers to support deck on the house side, hence ledger on house side.

Piers:

• Use piers to support deck on the far side of deck, away from house
• Piers should be cast-in-place concrete, 12 inches in diameter, cca 8 feet on center, depending on beam girth, to depth of frost line.
• Process: dig/drill holes in earth, place 3-4 inch gravel layer at bottom of holes, place forms from cardboard tubing, mark a level line on all forms (account for thickness/width of girders and joists when determining final level of piers), pour concrete to level lines.

Framework:

• Entire structural framework for deck should be pressure-treated or similarly decay-resistant wood.
• Use galvanized steel post holders on piers to raise posts above ground contact
• Place posts on post holders
• Place girders (e.g. 4x10 or doubled 2x10) across posts (parallel to house), joists across girders (perpendicular to house), decking across joists. Use bridging between joists for bracing.
• Keep in mind cca 2-foot cantilever allowance for both girders and joists

Two-level deck variation:

• Consider a two-leveled deck to avoid a dramatic drop-off from deck level to ground level in garden.
• Place first level's house-side girders on ledger and garden-side girders on posts/piers
• Place both of second level's girders on posts/piers, for a total of 3 rows of post/piers for the two levels

Short-ledger variation: First level has a smaller length (and so ledger attached to house is smaller), second level is wider. Construction as for two-level variation.

Other notes:

• Cover ground below deck with mill plastic topped with gravel, to avoid water migrating from ground up into deck.
• If/when placing rail posts for a fence/railing around perimeter, use a 6x6 at corners and 4x4 along straight edges, notching bottom end of posts to slide into framework of joists/girders. Try to bolt posts onto both a girder and a joist, for anchoring in two dimensions