[johnny67]

I'm at the point of building my deck extention that I am wondering

#1 how I will build the back wall/foundation to the garage underneath the deck and

#2 how I will waterproof under the stairs so I can have storage there seperate from the garage.

I will post some better pictures tomorrow.

 

[TazinCR]

If there is not going to be enclosed you need PT lumber. You should post a plan of what you need to do so someone here can guide you.

 

[johnny67]

The garage is 12' wide and I want to put a 36" door in the corner under the stairs landing. you can see in the pic where I layed out a 12' 2x4 to show where the wall will be. With the stairs leading down there will be some room for storage and I would like to build a wall there with a door. How would I make the stairs so now water gets to the storage underneath?

 

[Gary in WA]

You need to get a permit.

1-The stem wall needs a foundation. The new end wall needs a foundation.

2-The stem wall is not thick enough. It is a 4" dirt retaining wall, not a one story foundation wall, with footing below the frost line.

3-You need anchors at wall/concrete.

4-Need a sill sealer.

5-Need pressure treated bottom plates at all concrete.

6-Studs are too close on center. (Not a structural violation as the rest.)

7-Need stair landing footings for posts.

8. The stair stringer looks to be 1-1/2" to 2" taller on the top riser than all the rest. It appears to need to drop some more to get the treads level, with storage underneath.

9- The house window near the stairs needs to be safety glass- is that the new one?

10- Are there any zoning issues so close to your property line?

If you have a permit, these changes are required.

I can show the codes for all these violations if needed. Be safe, G

 

[kemp]

I hope you are planning on covering what you have built. It looks like the wood is untreated. I also hope that the deck slopes and that you are planning on using some kind of approved flat roof material. You haven't clearly stated that.

As far as keeping the future storage under the stairs from leaking. Well, that too requires a slope and proper roofing material.

If you are not planning on a flat roof design, you will need to consider options for protecting the deck joists.

 

[johnny67]

Kemp, Yes the top of the deck will have a fiberglass resin professionally installed on top of 3/4" tung and groove plywood. I have a 2% slope leading away from the house.

Gbar, the retaining wall is 8" thick and very solid It was originally desinged to hold the deck up, I am just extending the deck 12' further than the original. The studs are 2x6's 8" oc The joists are doubled 2x10's at 16"oc the house side wall is 2x4's at 8" oc to support my 2200lbs hot tub which will be placed closer to the retaining wall side as per instructions from an engineer. I have not installed all the concrete fasteners in the sill yet.


The wall I will be building will not be load bearing at all. I have now broken the concrete and will be putting a small retaining wall to support the 2x4 wall and 36" door I will be putting in. How deep I should go with the footing is what I am wondering. Temperatures get down to about 20 deg. F in the winter at the coldest. I will also put a footing for a 4x4 treated post to hold the corner of the stair landing.

 

[kemp]

You referenced having guidance from an engineer in your previous post. The engineer should have already told you how deep to go with the footing and how large to make it.

I believe that footings should always be under the frost line (look up your local frost line).