November 15, 2009

Beefing Up The Dining Room Floor

I've been saying for awhile now that our next house project is a new hardwood floor to replace the old linoleum in the dining room. Well, it is, but anyone who's done any renovation on an old home knows that there are often a lot of preliminary steps needing to be done before getting to the "real" project. It's been no different with our dining room floor. While to floor in that room is level (amazingly), it did have some give to it in spots. DH wanted to address this by adding additional support before we started nailing down the new flooring.

Our crawlspace is not ideal. It goes from about 3 feet at the back of the house, to barely inches in the front. The oil burning heater and air conditioner (pic here) were installed near the dining room which is about the middle of the house. To do this, they knocked a huge hole in the foundation. A concrete pad was laid and the unit placed on top of that. This meant that the largest of the ductwork was under the dining room, leaving no room to maneuver. To be able to work under there, DH pulled out the heater/AC unit, put a temporary header in the opening, and pulled out all the ductwork. Not only did this give him room to work, but also easy access to the dining room floor.

Where the heater wasNow, I admit that I am not without misgivings about this. Not because of the heater, but because of the AC. Not that we needed it all summer, but it was sure nice to have when we had days on end in the middle 90s. Regardless of that, the ductwork was in very poor shape. Parts of it weren't insulated or the insulation was falling off, so it needs to be replaced anyway.

We aren't the first ones to work on supporting the dining room floor. You can see the beam that was previously added in the photo below. It is supported by concrete blocks.

Old support beam under the dining room.This beam is 4x4 inches, and 8 and 1/2 feet long. The length of the dining room is 13 feet, so this only supported a portion of it and so was minimally helpful.

A problem that needed to be addressed was the bridging. Do you see the X's in the photo above? This is cross diagonal bridging. It's purpose is to prevent swaying of floor joist which cover a long span. While cross bridging is acceptable, the problem is that the bottoms of the X's are nailed into the bottom of the joist. They should be attached on the side of the joist, the same way as they are at the top of the X.

One more thing to be noted is what you can see between the floor joists. It is the underside of our dining room floor...

Bottom side of our dining room floor.We have no subfloor, just tongue and groove floor boards. On the top side is linoleum (photos of that in this post.)

Dan's plan was to start by installing a 14 foot support beam. He made it by putting two 2x6's together. You can see part of it in the very first photo. To support it, he wanted to use three piers of concrete blocks, and three jack posts, of which you can see two below.

Floorjacks at different heightsI had never seen these before. They can be purchased in different lengths, each of which is adjustable. He made his own footings for the piers, repurposing a discarded cardboard tube which was originally used to hold industrial rolled steel.

Footer moldHe strengthened the form with rebar, and then poured concrete into it. The concrete blocks were set on these.

New support beam in placeThe pier on the right is one of the new ones. The footing is on the bottom with concrete blocks supporting the beam. To the left of that is one of the floor jacks. The floor jacks enabled the beam to be raised just enough to slip the concrete blocks in place.

Actually, the concrete block pier you see between the two floor jacks is supporting the floor further back in the photo. What in the world that partially buried concrete block is doing there, we don't have a clue.

You can also see in the above photo that the cross diagonal bridging is gone. Dan replaced it with solid bridging, which is made of sections of a 2x8, cut to fit between each joist. In the photo, it almost looks as though these are placed directly on top of the support beam, but they aren't. It looks that way because of the angle the photo was taken.

Of historical interest, are the type of nails he found in the old bridging.

An old, bent, cutnailThese are cut nails. Unlike modern wire nails which are round, old-fashioned cut nails were made by cutting them from sheet of steel, giving them the squared appearance. The one I'm holding has been bent. They can still be bought today for anywhere from $8 to $12 a pound, and are used in restoration projects for an authentic historical look. An interesting history of nails can be found in this article, "All About Nails", at the Appalachian Blacksmithing Association website.

The last thing to be done was to put down black plastic on the crawlspace floor.

Starting to put the plastic downThis will help control moisture in the crawlspace with it's accompanying problems of mold, fungi, and mildew. It will also help prevent moisture from damaging the structural elements of the house such as the joists and sills, because moisture will eventually break down wood.

As you can see, we've just begun with that step. Still to be addressed ins the hole that was knocked out of the foundation, as well as places where the mortar is loose from the foundation bricks. Much work on that part may have to wait until summer and the return of warmer, dryer weather.

Once DH is satisfied with it, then we can begin with the flooring. Yay! But first, I should show you my own preparations in the dining room. I'll do that next time.

Beefing Up The Dining Room Floor photos & text copyright
November 2009 by Leigh at


Renee Nefe said...

Looking good!

Theresa said...

Oh ugh, what a hard space to work in. We've had our share of work but have always ben lucky enough to have a basement, never a crawl space. My sympathies,
but I'll be jealous when we see the new floor for sure. ;-)

Sharon said...

My kids spent summer vacations with their grandparents in Washington. They still talk about all the jacks holding up the floor. You can imagine how much anxiety that would cause in children.

Life Looms Large said...

I've never actually seen a crawlspace before. That looks like such hard work.

Up here, having dining room floor kind of open to the outside air like that would be freezing!! They don't make slippers thick enough!!

Good luck!!!


Leigh said...

I hope so, Renee!

Theresa, a basement was one thing on our "must have" list that we didn't get. We're both from the north were basements are common, in the south, less so. It would be so much easier to work on things (not to mention the extra space) if we had one.

Sharon, that's a hoot. I love how kids react to things.

Sue, I promise crawlspace isn't left open like that. Not only to protect the pipes, but to keep critters out! The oil burner used to be there, and for now Dan has it covered with plywood. Not sure what we'll do with it in the end. Either re-brick or put in an entry door.

Theresa said...


If it were my home, I would put the heater and duct work back, new duckwork if need be. There will come a day when the wood will be a heavy duty if not impossible even if only for a short period. Have the heat and a/c ready. Not only will help maintain the value of the home, but provide piece of mind. Gene occasionally has to travel in the winter and I am hard pressed to keep the big wood boiler going during those times, we always put some oil in the tank and Gene switches it over so the boiler works on the oil fired system as was originally installed. Now if I could just get someone to run the plow when he's gone! ;-)

bspinner said...

Good idea to fix this problem before putting in your new floor. I'm sure it will last a whole lot longer.

Julie said...

We've done that before in our very first home. It was built in the 30's and it was a great house we just out grew it!

Leigh said...

Theresa, we're contemplating another heat source besides wood, but not the oil burning heater. For one thing it's old, (about 13 years) and besides not wanting to buy oil, we suspect there were problems with it somewhere along the line and can't be certain it hasn't leaked in the past.

One of the possibilities we're looking at is a ductless mini-split system. We're still in the research stage at this point. The AC is one thing I insist on having. Sometimes it's the heat and sometimes it's the humidity, but I'm just getting too old to not have the option to air condition the house!

Barb, that was our thinking too. Plus Dan is big on solid foundations. We would have started with the foundation and worked our way up if the insurance company hadn't insisted on a new roof.

Leigh said...

Julie, you must have been commenting the same time I was responding! I would have loved to have seen your old home. Of course, building your dream home is nothing to sneeze at either.

Benita said...

You make my remodeling look like a cake-walk. You and your DH must be very proud of all the work you have accomplished since you bought this house and land. I get tired just reading about it, but what fascinating reading it has made!!

Lee said...

Ugh. I hate crawlspaces. Ours is about the average height of yours (one and a half feet), except some of the beams require a squeeze to get under. When I'm down there, I think about the odds of an earthquake here in the Northwest.

I thought your joist bracing was pretty funny. What is it with old houses? No one had a book for this sort of thing back then, so they just went by word of mouth?

Leigh said...

Oh Benita, if only that were true! Photos and a simple description help make it seems so. It's the days and weeks of research and deliberations that are tough, and then the uncertainty when you finally do sink your teeth into it as to whether or not you're doing it the best way. One thing we keep reminding ourselves though, is that the house has been here for over 80 years and is still standing, so there's no need to panic.

Lee, I have to tell you that Dan has shaken his head over a lot of things we've found here. He's done some looking around though, and realized that a lot of what we think is odd is pretty standard for similar homes the same age as ours. I wonder if you have found the same, and if building practices varied a lot in different parts of the country.