Sagging Bedroom Floor Required Replacing an Inadequate Beam
Our client had purchased a home that belonged to the family of her best friend when she was growing up. She remembered as a child that the house had been renovated to make the family room larger by removing a center dividing wall. Over the years the flooring above the removed wall had started to sag. It got so bad that the bedroom floor had about 2 to 2 half inch sag, or “belly”. Our client assumed that the previous owner, her best friend’s father, had commissioned work that did not include installation of a beam in the floor system to take the load of the removed bearing wall.
During our investigation, we went into a closet above the sagging area and cut out a small piece of flooring so we could access the existing condition of the structure. We determined that the previous contractor had replaced the bearing wall support with a beam. The beam was built out of three 2 x 10 inch heart pine timbers nailed together and inserted in the floor system to create what is known as a “flush beam”. Unfortunately the beam was not correctly engineered. Clearly a structural engineer had not run calculations to determine if indeed that hybrid beam would support the weight of the second floor wall and the attic above. As a result, the heart pine beam had deflected or sagged over the years from the weight above.
A structural wall is basically a series of posts or columns that support the weight above. That series of posts is known as a stud wall which is an incredibly strong support for structural loads from above. A column is extremely strong in compression. However, a timber is weak and tension. Detention was the beam that they had job site engineer need to span a 15 foot room. The weight of the beam was transferred to studs or posts and the body wall on both ends of the beam. Once we had good idea of the structural problems then we were able to design a solution.
Of course the most important part of the solution was correctly engineering the new structure to assuredly hold and support the weight above. Obviously we didn’t want the same problem to reoccur in the future. Luckily now they have what is known as LBL beams or engineering beam. What that means is the wood is specially designed stranded and glue together to transfer or carry more weight in tension than a normal would timber.
The LBL wood timbers are engineered beams that we used is short for laminated veneer lumber. Once we contacted the LBL engineering department they ran the load calculation and determined the size and the number of LBL beams that we would need to replace the failing beam that was installed over 25 years ago. Understanding the structural repair is a huge part of this job. Clearly the most important part. However the human part is also incredibly important as experienced renovation contractors we know the importance of and the sanctity of somebody’s home, you never want to go in and create a mess as the owners never forget and forgive when you trash or just dust their whole house.
As we always do when we are working in house where people are living and air conditioning systems are in service, we insist on making a hermetically sealed enclosure where we do the work and contain the dust. We did this on this job with frame parallel temporary structural walls to take the load for the old beam that we were removing and transferring it to the temporary wall while we were doing the structural improvement. The temporary structural wall helped us enclose the room but we had to install the plastic sheeting on all the walls and then sealed it with tape to the existing ceiling, walls and floor on both sides. Any small area where air can flow through can put a tremendous amount of dust into a clean room in a short while. Clearly a huge structural repair in the midst of a home where the homeowners are living and the family is living is critical to do it with the structural factor in mind and the human factor, both are equally important to producing a successful job with happy homeowners.