What is a Lally Column?
A lally column, named after its inventor Samuel Lally, is a hollow steel pipe with threaded ends. Steel base plates with holes are welded to the ends and allow the column to be bolted to the floor and ceiling. The height of the column can be easily adjusted by twisting the inner shaft up or down.
Lally columns are used to support structural loads and prevent sagging, bouncing, or bowing. They are commonly installed beneath floor joists, beams, and headers to provide additional support. Lally columns are an ideal solution when:
- Additional support is needed beneath an existing structural member
- Posts or columns need to be installed on uneven surfaces
- The load needs to be transferred to the foundation or lower floor
Benefits of Using a Lally Column
- Adjustable height – The telescoping design makes it easy to adjust the height even after installation. This allows the column to be customized for various floor-to-ceiling heights.
- Easy to install – Lally columns come ready with baseplates so no special brackets are needed. Just bolt to the floor and ceiling. No welding required.
- Cost effective – Provides an affordable method to support and level floors compared to other alternatives.
- Transfers load effectively – Solid steel construction enables lally columns to support heavy structural loads and transfer it to proper footings.
- Aesthetic versatility – The hollow pipe design allows lally columns to be boxed in and hidden for a seamless look after installation.
When to Use a Lally Column
Lally columns should be used when:
- Additional support is needed for sagging floors
- A beam, header, or joist needs more support
- The floor structure is uneven and needs leveling
- Load needs to be transferred from upper floors to the foundation
- Vertical support is required but space constraints prevent using a standard post
Lally columns are commonly used in basements, garages, crawl spaces, and areas prone to settling. They can support finished living spaces above by transferring the load past plumbing, ductwork, or low headroom areas in basements.
How to Determine Correct Lally Column Size
Lally columns are available in different diameters and weight capacities. To select the proper size, you need to calculate the load that will be imposed on the column.
The key factors are:
- Total weight of the structure and objects above
- Span of the beam or joist being supported
- Spacing between existing supports
- Maximum load recommended for the floor or roof structure
This loading information can be obtained from architectural plans or by consulting a structural engineer.
As a general guideline:
- 3-inch diameter lally columns can support up to 6,000 lbs
- 4-inch diameter lally columns can support up to 12,000 lbs
- 6-inch diameter lally columns can support up to 21,000 lbs
Match the column capacity to the structural load. It is better to err on the larger side.
How to Install a Lally Column
Tools and Materials Needed
- Lally column kit (comes with column, base plates, coupling nut, and bolts)
- Wrench or ratchet with sockets
- Drill with concrete drill bits
- Hammer
- Level
- Shims
Step 1: Determine the exact installation location based on where additional support is needed. Use a level to identify sagging beams or areas with uneven floors.
Step 2: Mark the floor and ceiling locations directly above one another where the lally column will be installed.
Step 3: Drill holes in the concrete floor and ceiling as per the baseplate diameter.
Step 4: Use a hammer to knock the concrete anchor sleeves into the drilled floor holes.
Step 5: Place the bottom baseplate and insert concrete anchors. Tighten nuts with wrench to secure the baseplate.
Step 6: Thread the top coupling nut all the way down the lally column shaft. Leave some extra threading.
Step 7: Place and align lally column over the bottom baseplate.
Step 8: Have a helper lift the column up and insert the top end through the ceiling. Thread top nut onto column.
Step 9: Use shims and level to plumb the column. Tighten top nut until snug and column is plumb.
Step 10: Tighten bottom nuts to secure column in place while checking plumb level.
The lally column is now installed and ready for the load. Monitor periodically and adjust top nut as needed. Boxing in the column can help conceal it. Proper installation is key for structural integrity and performance. Consult a professional if unsure.
Safety Tips When Using Lally Columns
- Have the floor structure evaluated to verify it can support the transferred load
- Ensure the column rating matches the intended load
- Install columns on center below the beam or joist, not off-center
- Use quality concrete anchors for maximum holding power
- Check for plumb and level during installation
- Do not exceed the rated capacity of the column
- Monitor the installation and re-adjust if any loosening occurs
- Hire a structural engineer for proper sizing and placement on load-bearing walls
Frequently Asked Questions
How low can I adjust a lally column?
The minimum installation height is around 4 feet. The top and bottom threads need sufficient overlap with the coupling and base plates.
Do I need a concrete footing for lally columns?
For light duty residential use, the concrete floor is typically sufficient. Heavier loads may require a concrete pier extending below the frost line.
Can lally columns be installed outdoors?
Yes, lally columns work for outdoor installations but will need to be protected from moisture damage. Use a weatherproof covering or enclosure.
What is the maximum height for a lally column?
Lally columns can be extended up to around 10 feet safely. Greater heights are possible but may require additional stabilization.
Can I install a lally column in the basement ceiling?
Yes, lally columns can support floors from underneath by transferring the load through the basement ceiling to the foundation.
Conclusion
Lally columns are an easy and affordable way to provide supplemental support beneath structural beams, joists, and floors. With proper sizing and installation, they safely transfer the weight to the floor below or foundation. Monitor lally columns regularly for plumb and loose nuts. Hire a professional engineer for guidance on large load-bearing installations. Used properly, a lally column is an invaluable tool for renovators and DIYers.