enclosing porch over earth "floor"

[ALPS]

Currently, my 6'x10' back porch sits 3' above the ground and shares it's foundation on two sides with the house, a third side is poured and the fourth totally open. The porch floor is slats (like a deck) and has a roof over half of it, but the sides and staris are open.


I plan to completely remove the porch, steps, roof, etc, build a new fourth side for the foundation and build a new room from there.

My goal is to enclose the porch, making it into and entryway, or coatroom, giving us a place to take off our shoes and coats before stepping into the kitchen.


My concern is that this new finished part of the house will be built over dirt, and under it will not be accessable fom the basement. The floor will be insulated, but the room not heated, and it will have a decent door separating it from the kitchen.

I'm guessing moisture will be a issue from the bare dirt under the floor and I want to prevent any problems this may bring. My first thoughts are to lay down plastic over the dirt and install a vent,or even a small access door, on my fourth foundation wall for ventillation.

Should I even enclose this porch over dirt? What can I do to prevent damage from moisture? Any other thoughts?

 

[Daryl in Nanoose]

Great idea, yes you will need ventilation, get the vents you can open in summer and close in winter. a access door is a must. You will want to put a ground seal down(plastic) and tape it to the walls to keep the moisture out. Now this is a great time to put a 2" skim coat of concrete and then insulate the inside of the foundation with rigid foam with the highest r value you can get.

 

[Square Eye]

Building code requires 1 standard vent for every 150 sqft of living space.
Plan on 4 vents. It would be good if you could cut 2 those into the poured wall.
The vents will be more effective if they are not all on the same side.

I have used plain black roofing tar to fasten plastic to concrete walls. Works great.
Learned that one from Glennjanie

 

[inspectorD]

My idea would be to seal the dirt floor with some plastic and a 2" layer of concrete. Then cut a hole into the basement wall through to the crawl space ...enough to have at least a 3'x3' access. There are companies who cut concrete, it is about $250 in my area for this hole.

This gets you away from having to install vents which do not work in my opinion.
You end up conditioning this small space with basement air..and a dehumidifier.
Also better for your stored belongings to be in a constant temp.

We do this on all our remodels when there is a crawl space..no issues yet.

Good luck with your project.

 

[ALPS]

My idea would be to seal the dirt floor with some plastic and a 2" layer of concrete. Then cut a hole into the basement wall through to the crawl space ...enough to have at least a 3'x3' access.

I think concrete would be the way to go to avoid any problems in the future. An access hole from the basement would be ideal, but the only poured wall under the porch is the exterior one. The other two sides share the houses 100 year old stone foundation. My access doorwould have to be outside in the yet-to-be-built fourth wall.

 

[Daryl in Nanoose]

This sounds like a real fun project keep us posted on your progress ( pics would be nice to). I to have a 6x10 and I do not know how I ever lived without one. It is a real nice feeling coming into my house with a nice entry even though mine is a front entry I would do this even as a back entry or off a garage. Thought I would show you mine just for the ___ of it.