It would reduce the first floor height by about a foot possibly making a 2 or 3 step entrance only 1 step. There would be some additional cost for bolting a pressure treated ledger to the foundation wall and installing steel hangers. Visually it would lower doors, windows, porches and decks by about a foot which might interfere with landscaping and reduce first floor privacy. All stoops, porches and decks would probably need to be poured concrete on grade.

I suspect this configuration would be feasible in warm dry climates.

This system isn't unusual, especially in the West Coast. The metal bracket shown in Mushcreek's photo is called a "joist hanger," it's a standard part.

Just another way to frame a floor. Any particular reason why your builder want to do/is doing this?

Thanks everyone!

Our builder is doing the dropped floor so we won't have as many stairs in the front or back of the house which we didn't want. We'll still have steps of course being on a crawl, but at the patio door it might only be one instead of 3 for example.

A "dropped" floor design works best for a house that does not have a basement or a vented crawlspace and the designer of such a house might opt for a slab on grade.

It also works best for houses designed to be open to the outside with privacy provided beyond the perimeter of the house.

Houses in northern climates must have footings 4 to 5 feet below grade so basements are therefore pretty cheap spaces and basement windows are desirable so that often puts the sill heights of ground floor windows above the eye level of someone standing outside. Additional privacy is provided by most bedrooms being located on a second floor due to heating considerations.

In warmer climates one story houses with ground floor bedrooms are more common and a window sill might be at the waist of someone standing outside. That is comfortable for some owners and unacceptable for others.

These are often more important considerations than the number of steps at the entrances.

JDS, why are dropped floors not ideal for vented crawl spaces? Ours will be vented and we are located in Eastern WA (not much rain like Seattle). We chose a Crawl because we wanted to have easier access to plumbing, etc and slabs are so hard underfoot. The number of steps wasn't a factor on whether to do crawl vs slab, the dropped floor was decided by the builder when we were deciding on how wide to make the patio door landing based on the number of steps it would have.

There would not be enough space for crawlspace vents unless an opening was cut through the perimeter floor ledger.

But I would avoid ventilating a crawl space in any climate.

^ Maybe radon?

We are doing dropped footings also. No vented crawlspace. Apparently vented is not common these days. As JDS stated, the grade comes up to the footing, so there is no place for vents.

We chose this system because we don't want steps on the ground level. None. Thinking forward for handicap/wheelchair access. We've seen the builder do this with other homes and we much prefer it. Bedroom doors to the patio come out without steps. This won't work if you want a deck as the deck must be above grade, not AT grade. This house will have covered patio and we wanted to walk out the back doors without any steps.

Crawlspace is easier for utility access than slab on grade, although we considered slab on grade which would do the same. Having had termite issues in previous houses, slab on grade doesn't appeal to me.

Also, the foundation was poured inside foam forms. I'm told the foam adds insulation in the crawlspace when closed up.

--Russ

(This is how they did it)

Hi Lisa, we're building a house in Eastern WA (Spokane) right now and the builder is also installing a dropped floor on a 4ft crawl space. We have many crawl space vents. What has been your experience so far?

The wood still needs to be 8" above soil grade, so there is room for vents, just maybe not the common sized ones. If you are not trying to get all the way to handicap access (no steps), there are often two sill plates between the foundation and subfloor (an extra one to cover the bolts), giving an additional 3" for vents.

We like to do "dropped floors" (eliminate or reduce wooden floor band or rim) for several reasons. As mentioned, it's easier to eliminate steps entirely for better accessibility, higher backfill (which comes with other issues raised by JDS), better air-sealing and typically better insulation continuity. It also reduces error with different panelized wall system integrations like pre-cast concrete + panels meant for above grade. Sometimes, there are cases for easier uplift resistance.

Our region is blessed with plenty of topography which usually mutes crawlspace or head height issues. You can always adjust wall height.

Jared,

So far our dropped floor on a crawlspace is fine, no issues. We hired a home inspector before closing on our new house and he said they are very common in this area. We just moved in a few days ago. :) We have about 3ft of headroom in the crawlspace. We ended up having one step down to the back patio and three at the front of the house (two actual steps plus the porch itself).

Lisa G, I've been watching on the "Building A Home" forum to see if you commented there. Since I haven't seen anything there, I decided to comment here to ask you how things are going. (Sorry for the temporary diversion from the original topic.)

Did the house close on 6/30, as anticipated? Have you moved in? And, most importantly, did the issues with the flooring get resolved to your satisfaction? If you don't want to hijack this thread, maybe you could post in the "Building A Home" forum with an update. I'm sure I'm not the only one interested in how things have turned out for you and your family.

sail_away, we've been so busy lately I haven't had a chance to update there! I'll go post a quick update there now. :)

Just read your update, Lisa, thanks! I responded there as well.

Houses in northern climates must have footings 4 to 5 feet below grade
so basements are therefore pretty cheap spaces and basement windows are
desirable so that often puts the sill heights of ground floor windows
above the eye level of someone standing outside.

However, the combination of severe height restrictions and luxury homebuyers' desire for high ceilings can often result in putting entries and first floors very close to the ground. Certainly that's the case in much of the Greater Toronto Area. To make up for the loss of basement windows, large walkouts are usually installed at the rear of the homes. Since main floor master suites are extremely unusual, the privacy question isn't as much of a concern. (Of course, I remember a friend who one morning turned to see a man looking in at her through the second floor bathroom window.)

I am also considering about the drop floor system, and to hide all cables underneath the floor. Do you if it is possible to do?

One of my clients also had this request to hide all the cables underneath the floor. On the other hand, my experience shows that this is not practical in most cases. Sometimes, people change the TV and internet providers, and obviously, providers need to have access to all cables, and sometimes to replace them. One of my colleagues found out about Netfloor USA. They produce floors that allow hiding all the wires and unwanted staff underfloor, and you can easily access them in case you need it. We ordered those floors for a few clients several months ago. They haven’t complained yet about the quality or something else. I think you can try them as well.

Drop down floor trusses are used alot if your poired walls are ten foot it helps keep basement height ceil to 8 foot.

" if your poired walls are ten foot it helps keep basement height ceil to 8 foot. "

Grady Matheson Feeding the troll spammer here I am sure, but why go to the expense of a 10' basement only to drop the flooring system to keep a 8' ceiling height in the basement?

Exactly!

I eliminated the reverse veneer speced by the architect, thus saving many thousands on the forming and giving us a basement ceiling height of 9 ft. Just had to be careful on the building's overall height to stay within the height limits.