If you own an Eichler in Mountain View, Palo Alto or Sunnyvale, there is
something under your floor that changes how termite work has to be done, and a
lot of homeowners do not know it is there until someone proposes drilling.
The short answer
Many Eichler homes were built with radiant heating: hot water pipes embedded
inside the concrete slab. Standard soil treatment for subterranean termites
involves drilling through that slab to inject termiticide underneath. In a house
with radiant piping, a drill bit in the wrong place punctures a heating line
inside the concrete — an expensive repair that requires opening the floor.
This does not mean an Eichler cannot be treated. It means the approach has to
account for the slab before anyone picks up a drill.
What makes these houses different
Joseph Eichler’s subdivisions went up across the mid-Peninsula in the 1950s and
60s, and they share a construction vocabulary that has aged into a specific set
of inspection challenges:
- Radiant slab heating. Piping cast into the concrete floor. Efficient,
quiet, and invisible — which is the problem. - Post-and-beam framing. Structural wood is exposed by design rather than
hidden inside walls. - Low-slope roofs. Less water shedding, more opportunity for standing water
and slow leaks. - Slab-on-grade with no crawl space. There is no subarea to inspect from
below. - Floor-to-ceiling glass and wood siding that often sits close to grade.
Each of those was a deliberate design choice. Together they produce a house that
a general pest control approach does not fit.
Why the slab matters for subterranean termites
Subterranean termites nest in soil and travel up into the structure. Treating
them usually means establishing a treated zone in the soil around and under the
foundation.
On a conventional foundation with a crawl space, much of that work can happen
from the subarea. On slab-on-grade construction, reaching the soil underneath
often requires drilling through the concrete at intervals and injecting
termiticide into the ground below.
That is a routine procedure on a standard slab. On a radiant slab it is a
procedure with a consequence attached, because the pipes are not visible and
their exact routing is frequently undocumented after seventy years of ownership
changes and remodels.
What a careful approach looks like
There is no way to make drilling into an unknown slab risk-free. What can be done
is to reduce the unknown:
Establish whether the system exists and whether it is still in use. Plenty of
Eichlers have had radiant systems abandoned in place, with forced air or
mini-splits added later. An abandoned line is still a line in the concrete, but
the stakes of hitting one are different.
Look for original documentation. Some owners have plans. Most do not. When
they exist they are worth more than any amount of guesswork.
Scan before drilling. Detection equipment can locate metal in concrete. It
reduces risk substantially. It does not reduce it to zero, and any company
telling you it does is overselling the tool.
Consider whether drilling is necessary at all. Depending on what the
inspection found, perimeter treatment, targeted work at points of entry, or
addressing the conducive conditions directly may address the problem without
penetrating the slab.
Get the tradeoff in writing before work starts. The owner should be the one
deciding whether to accept the risk, with the risk stated plainly rather than
buried.
The other Eichler problem: access
The slab gets the attention, but for inspections the bigger limitation is often
what cannot be reached.
No crawl space means no subarea inspection. Low-slope roofs frequently have no
usable attic. Built-in cabinetry and full-height glazing cover wall areas that
would be examined in a conventional house.
In practice this means Eichler reports carry more further inspection
recommendations than average — notations that a specific area could not be
examined. That is not an inspector being unhelpful; it is the honest description
of a house that was designed without the access points inspectors normally use.
If you are buying an Eichler, read those notations carefully. They are the parts
of the house nobody has actually seen.
Water is the recurring theme
The condition that most often shows up in these houses is moisture, and it
follows from the design.
Low-slope roofs hold water longer. Wood siding near grade wicks it. Post-and-beam
members that are exposed by design are also exposed to weather. Add irrigation
aimed at a wall and you have the standard recipe for fungus damage — dry rot —
which in these houses is frequently a larger line item than the termites are.
Most of what protects an Eichler is unglamorous: keep drainage moving away from
the structure, keep siding out of contact with soil, fix roof leaks early, and
keep sprinklers off the walls.
If you own one
The short version: tell whoever inspects your house that it is an Eichler, and
ask directly how they handle radiant slabs. If the answer is vague, or if
nobody mentions the slab until the drill is already in the truck, get another
opinion.
These are good houses. They are also specific houses, and they reward being
treated as such.
J&M Termite Control has worked on Peninsula homes from Mountain View since
1973, under California Branch 3 registration #5223. We hold a CSLB general
building license, which means the repair side of a report is handled in-house
rather than handed to a separate contractor.
Request an inspection, or read
about our services and
what happens during an inspection.
