Structure: Supporting the house from the basement

Structure: Supporting the house from the basement

Our house had several structural issues that overwhelmed me as a do-it-yourselfer. I am not ashamed to admit that I turned to the pros for help. We had been living for years without use of our second floor. On the main floor, the ensuite had been gutted and we knew we had to replace a supporting wall that the previous owner had removed. We consulted with an architect and hired a couple of contractors to renovate and restore our house. (I blogged about that renovation starting here).  The contractors started in the basement. When dealing with structure, start at the lowest point and work up. Structure is only as good as the support under it.

Sagging load-bearing joists

First of all, it is important to note that the basement is divided into a workroom area and a recreation room area by a load bearing block wall. In the workroom, which is below the bedroom and bathroom, the double joists which supported load bearing walls above (one which was removed by the previous owner) had sagged significantly over the years. The contractors’ first course of action was to support the joists from below and bring them up to level.

jack posts
Three jack-posts were needed to get rid of the 3/4″ sag in this double joist.  The posts were replaced by a stud wall.

Using a few jack posts, they cranked up the joist until it was level, and then built a stud wall underneath. The new stud walls in the basement carry the load above. As a result, the workroom is now divided into three rooms. A new basement bathroom was build directly under where the main floor bathroom was originally, before the previous owner did his renovations. This allowed us to have a functioning bathroom while our own renovations were being done.

framing and structural support
The framing for the bathroom walls helps support the structure above.

Jacking up the joists did cause some damage on the main floor and on the second floor as the movement resulted in cracks to drywall and plaster. This was to be expected. Any damage on the main floor didn’t matter, since this side of the house was going to be completely gutted anyway. And the damage to the second floor wasn’t anything some drywall compound and paint wouldn’t fix. A few cracks in the wall now is preferable to more damage in the future.

stress crack
The resulting stress crack in the main floor bathroom

 

Support Beam

In the recreation room portion of the basement, floor joists are supported by a main beam that runs the length of the room. The problem here was that the beam stopped at the chimney, leaving another 8 feet or so unsupported. Without any use for the chimney (it had been removed to just below the second floor), I had the contractors remove the rest of it, since extensive renovations were already taking place. That freed up the space to allow them to continue the beam across the rest of that portion of the basement.

support beam
The new section of the main support beam, supported by a 2×6 stud wall.

A new 2×4 stud wall helps support the beam where the new section meets the old section. The wall replaces the one that was there previously, closing off the boiler room from the rest of the rec room.

The Basement Window

Another glaring example of the previous owner’s penchant for installing oversized windows with no regard for the structure around them was the basement window. A typical basement window was replaced with a picture window allowing a lot of light into the basement and providing beautiful view of the picturesque back yard. However, outside there was no lintel installed to support the bricks above the window. Inside, he had sacrificed the support for the floor joists and framing.. To make matters even worse, the window was installed right at ground level. Without a window well, the wood frame had suffered extensive water damage and the window was prone to leaking during heavy rains.

basement window
A steel angle iron lintel was installed to support the bricks.

The solution was to remove the old window, which was near the end of its life anyhow, The ledge was built up several inches with poured concrete, raising the window above the ground. Outside, the bricks were notched on either side of the window so that a steel angle lintel could be installed to support the brickwork. Aluminum capping was later installed. Inside, a steel angle supporting the floor joists is itself supported by wood studs.

basement window
Concrete was added to the block to raise the window off the ground, creating a smaller window opening.

Structural Repairs: How to “unbutcher” a house

The Back Dormer: Repairing water damage and fixing framing problems
The Back Dormer:  Adding ventilation and eliminating water leaks
The Sunken Tub
Supporting a house from the basement up
Load-bearing walls

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