Our HOA is sitting on our flooring request. What does California law require of it?

Civil Code 4765 applies when the governing documents require approval. The association's procedure has to state a maximum response time, the decision must be in writing, and a denial must explain why and describe how to ask the board to reconsider, which happens at an open board meeting. Check your HOA's published procedure for its deadline.

The underlayment box says IIC 70-something. Will my floor test that high?

Not necessarily. The NWFA says impact noise depends on the entire floor-ceiling assembly: the flooring, the slab or joists, and the ceiling below. A rating only holds for the build-up that was tested. Ask for the lab report, then compare its slab, flooring and ceiling against your own building.

Our unit sits over the garage. Do the sound rules still apply?

The building code's impact rule for floors between units doesn't apply over nonhabitable spaces such as garages, mechanical rooms or storage. Your HOA's own rules may still require an underlayment or a rating everywhere, though, and they can be stricter than the code. Read the CC&Rs and flooring policy before choosing a product.

Can solid oak be nailed down over a sound mat?

The NWFA's sound control guidance says nails should not pass through the sound control material into the subfloor, because each fastener carries impact noise past the mat and greatly cuts its performance. That is why most condo jobs use floating or glued engineered floors, or a mat system designed for the method.

What is the difference between IIC and NISR?

Both score impact noise, such as footsteps, from the floor above. IIC is measured on a floor-ceiling assembly in a lab under ASTM E492, and California's code asks for at least 50. NISR is measured in the finished building under ASTM E1007, with a minimum of 45. Higher numbers mean quieter.

Condo Hardwood Flooring in Torrance, CA

Torrance Wood Flooring is a no-charge phone line to an installer who lays wood over sound mats in shared buildings. Send us your HOA's flooring rules and the unit size; the installer calls back.

Typical cost: engineered hardwood runs $9 to $20 per sq ft installed in national guides, and underlayment adds $0.50 to $1.00
Timeline: 1 to 3 days to install, after the HOA's written approval
Code target between units: IIC 50 in the lab or NISR 45 in a field test
Tested example: 12 mm hardwood on a 5 mm rubber mat over a bare 6 in slab rated IIC 55

Condo Hardwood Flooring Methods for Shared Floors

Torrance has 13,624 homes in buildings of 20 or more units, and in every one of them somebody lives under somebody else's floor. That makes a condo wood floor a sound job first and a flooring job second. The mat underneath and the HOA's rules decide the method.

Engineered oak planks being laid over a gray acoustic underlayment in a condo living room

Acoustic Underlayment Under Floating Floors

A floating engineered floor clicks or glues together at the edges and rests on an underlayment, never fastened down. National guides price ordinary underlayment at $0.50 to $1.00 per sq ft; rated acoustic mats can cost more, so get the mat priced as its own line. The floor has to stay clear of walls and molding: the NWFA says a small gap at the perimeter keeps footfall noise from traveling into the wall, where there's no sound control. The product side (wear layer, core, click systems) is on Engineered Hardwood Installation.

Rubber sound mat glued to a concrete floor with a few engineered planks bonded on top

Glue-Down Over a Sound Mat

Some mats are bonded to the slab and the wood is glued to the mat. Use only adhesives and mats the maker lists together, and ask for a test report for that exact build-up. One lab test of 12 mm hardwood over a 5 mm rubber mat on a bare 6 in slab gave IIC 55 and a 25-point improvement over the slab alone. That's a single product on a lab slab with no ceiling below, so treat it as a sense of scale, not a promise.

HOA Approval and IIC Test Reports

Where the governing documents require approval for a change like a new floor, California's Civil Code 4765 requires the HOA's procedure to state a maximum response time, and a denial must come in writing with reasons. Send the board what it needs to decide quickly: the flooring product, the underlayment's lab report, and the installation method. The NWFA notes that association covenants can be stricter than the building code, so the CC&Rs, not the code minimum, set the bar.

Finished engineered oak floor in an upper-floor condo with a gap hidden under the baseboard

Upper-Floor Units Over Concrete

If the subfloor under your carpet or tile is concrete, it still needs a moisture test before wood goes down, explained on Hardwood Floors Over Concrete Slab. Leave the nail gun out of it: NWFA guidance says nails through the sound mat into the subfloor greatly reduce its performance.

Open boxes of oak flooring boards acclimating in an empty room, with a moisture meter resting on a board

Why Torrance homeowners call Torrance Wood Flooring

Free to call or use the form; the referral costs you nothing
Your request goes to one independent contractor, not a bidding list
Ask for a moisture reading and a written line-item estimate
California caps the down payment at 10% or $1,000, whichever is less

Condo Floor Sound Ratings: IIC, NISR and Delta IIC

The California Building Code (section 1206.3) sets the floor between two homes, or between a home and a public or service area, at:

IIC 50 or more
, tested in a lab under ASTM E492, or
NISR 45 or more
, if field tested in the finished building under ASTM E1007
No impact rating over nonhabitable spaces such as garages, mechanical rooms or storage

Underlayment makers also quote delta IIC, the improvement a covering adds over a bare slab. It's useful for comparing mats, but it isn't the number the code asks for. The NWFA's advice is to compare only certified lab results and request full copies of the reports.

What to Get in Writing Before Ordering Condo Flooring

The HOA's flooring rule
, including any required IIC, NISR or named underlayment
The underlayment's lab report
, with the slab thickness and ceiling it was tested on
The method
: floating, glued to the mat, or something else, and why
Perimeter detail
: how the gap at walls and trim will be left and covered
The board's written approval
before any material is ordered

Contract and deposit rules for California home improvement jobs are on the homepage.