The Building Is Occupied. The Walls Are Plaster. Now What?
VALUE-ADD & RETROFIT INSIGHTS
How to modernize security and connectivity in a value-add asset without a full rewire.
The new-construction version of this conversation is easy. Open walls, a coordinated drawing set, and a general contractor whose job is to accommodate you.
The value-add version is not. You have a 1968 garden-style community or a 1920s mid-rise with plaster and lath, a wiring closet that was a broom closet, coax that was pulled for cable television during the first Bush administration, and 240 households who live there. Every unit you need to enter belongs to someone who has to be home, or has to trust you to enter when they are not.
This is where most property technology projects quietly die. Not because the owner does not want the outcome, but because the standard answer is unaffordable and the alternatives are poorly understood.
Why "just rewire it" usually fails
Ask a low-voltage contractor how to bring gigabit connectivity and a modern security posture to an older asset, and the default answer is a structured rewire: new Cat6 to every unit, new pathway, new closets.
$700 to $1,100 per unit is the range. Industry discussion of brownfield MDU deployments puts on a full structured rewire, before you account for crews, open walls, and the disruption to residents' lives. On 240 units, that is a number that has to compete with roofs, HVAC, and unit interiors in the capital plan, and it usually loses.
Source: Calix, industry panel discussion on brownfield MDU deployment economics
But cost is not actually the thing that kills these projects.
Disruption is. Practitioners who do this work for a living consistently report that in an occupied building, resident disruption is the real deal-breaker rather than dollars. Consider what a rewire asks of you operationally: coordinating access to every occupied unit, often twice, cutting and patching finished walls, managing dust and noise across a community where people work from home, absorbing the concession requests, and doing it on a schedule that no one can hold precisely. Then multiply the resident-relations cost by the number of five-star reviews you were counting on this year.
WORTH SAYING PLAINLY
There is a reason older buildings get bypassed. It is not that owners do not care.
The alternative: use the wire that is already there
The technology that changes this math is G.hn, an ITU standard designed specifically to deliver gigabit service over the wiring older buildings already have, meaning existing coaxial cable or existing telephone pair
The practical characteristics matter more than the standard number:
● It runs on existing coax or twisted pair. Positron's G.hn access multiplexers deliver gigabit service up to roughly 2,600 feet over existing RG-6 coax and up to roughly 800 feet over existing telephone pairs, which covers the vast majority of real buildings.
● It reuses the existing splitter topology. Over coax, G.hn supports point-to-multipoint operation through the CATV splitters already installed in the building, serving multiple subscribers from a single port rather than requiring a home run to each door.
● It does not fight the cable plant. G.hn operates in baseband spectrum and avoids the spectrum overlap issues that complicate other approaches, so it can coexist with existing services during a transition.
● Per-subscriber capacity is not the constraint. Each subscriber port supports well over a gigabit of dynamically allocated bandwidth, near symmetrical, which means the limiting factor is the fiber or fixed wireless feed into the building rather than the in-building distribution.
Half the cost, 45 minutes
Reusing existing coax and copper cuts the per-unit cost of the deployment to roughly half of a structured rewire, with in-unit installation time averaging in the neighborhood of 45 minutes.
Source: Calix, industry panel discussion on brownfield MDU deployment economics
Forty-five minutes, once, with no wall opened, is a completely different conversation with a resident than a two-visit rewire. It is the difference between a project that gets approved and a project that gets discussed every year and never happens.
The security side of the same problem
The wiring constraint shapes the security scope too, and the same principle applies: choose the approach that respects what the building already is.
1. Access control
Wireless and offline-capable lock platforms have improved enormously, and they eliminate the need to pull power and data to every opening. Reserve hardwired, fully monitored openings for the doors where it genuinely matters, typically main building entries, garage and gate access, package rooms, and amenity spaces, and use wireless credentials for the long tail.
2. Cameras
The exterior and common-area positions that produce actual value are far fewer than a total-coverage design implies. Approach paths, garage ramps, package and mail areas, and the routes residents walk after dark do most of the work. Existing coax can often be reused for camera transport as well, which removes the largest cost driver from the estimate.
3. In-unit devices
Smart thermostats, leak sensors, and smart locks install during turns rather than as a separate project, which is the single most useful sequencing insight in a value-add retrofit.
Sequence around turns, not around a project schedule
The best retrofit plan for an occupied asset is usually not a project at all. It is a standard that attaches to work you were already going to do.
● Common areas and infrastructure first. Head-end, distribution, exterior cameras, and controlled entries can be completed with minimal unit access and deliver most of the security benefit immediately.
● In-unit connectivity as a scheduled sweep. A 45-minute install is short enough to batch by stack or floor with reasonable notice and a high consent rate
● In-unit devices at turn. Every unit turns eventually. Attaching the device package to the turn standard means the retrofit completes itself over a normal cycle at close to zero incremental disruption and lets you charge for the upgrade as it lands.
That last approach converts a capital event into an operating rhythm, which is generally how value-add technology should be handled anyway.
What to check before you commit to anything
A credible retrofit plan starts with a site survey, not a proposal. The questions worth answering first:
● What wiring actually exists, where does it run, and what condition is it in? Assume the as-builts are wrong, because they usually are.
● Is the coax plant home-run, splitter-based, or some undocumented hybrid, and where are the splitters?
● What is the riser and closet situation, and is there space, power, and cooling for a head-end?
● What service is available at the property line, and what does the fiber or fixed wireless feed cost to bring in?
● Which doors genuinely need hardwired access control, and which can be wireless?
● What is the turn schedule, and can the in-unit scope ride it?
Any partner who quotes a retrofit without walking the building is quoting a template.
THE SHORT VERSION
The constraint was never the building. It was the assumption.
An older, occupied asset is not a bad candidate for modern security and connectivity. It is a candidate for a different method.
Rewiring is one answer, and sometimes the right one. But for most value-add buildings, reusing the wiring that is already in the walls delivers the same resident-facing outcome at roughly half the capital cost, in about 45 minutes per unit, without opening a single wall
Let us walk your building
GreenMarbles designs and deploys connectivity, video monitoring, access control, and in-unit technology for occupied and value-add multifamily assets, including retrofit deployments that reuse existing coax and telephone wiring rather than requiring a structured rewire. Nationwide installation, U.S.-based support, and one accountable partner from survey through service.
Send us an address, and we will tell you what is actually in the walls and what it would take.
Andrew Gulick, PGA
Vice President, Commercial Services
andrew.gulick@greenmarbles.com
General inquiries: Sales@GreenMarbles.com
SOURCES
● Calix, industry panel discussion on brownfield MDU deployment economics, including structured rewire cost ranges and G.hn per-unit installation times
● Positron Access Solutions, published G.hn Access Multiplexer specifications for distance, topology, and per-subscriber capacity over existing coax and telephone wiring
● ITU-T G.9960 G.hn standard documentation
