Frequently Asked Questions

Why do I need both a Geotechnical and a Structural engineer?

The geotechnical engineer recommends the appropriate pile system(s) i.e. pile type, pile capacity and anticipated pile depth. These recommendations are determined largely by the site specific soil conditions. Also, they perform onsite inspections and generate field reports for the general contractor and the building department.

The structural engineer incorporates the geotechnical engineer’s pile design recommendations, found in the geotechnical report, to design the foundation system including: how many piles are required, exact placement of each pile, top plate design and grade beam design.

Can you recommend some names?

We oftentimes recommend geotechnical engineers or structural engineers who are familiar with various pile systems. Please call for recommendations.

Why don’t you do the pile layout?

Pile surveying (staking) should be done by a licensed surveyor. Surveyors have access to sophisticated equipment to set pile locations precisely given the property lines. Pile placement is critical and margin for error should be plus or minus just a fraction of an inch. This is not something that should be trusted to field measuring using a metal tape measure.

Do you weld the pipe sections and top plates? Why not?

McDowell Pile King has developed a sleeved coupling system for joining pile sections together. Onsite welding is slow and costly when waiting for pile sections to be welded. McDowell Pile King’s pile top plate system utilizes the same sleeved method as the pile couplers.

Does the City or Building Department inspect the Piling?

Pile inspections or special inspections are performed by geotechnical engineers. The building department relies on the geotech of record to document and record the installation process via daily field reports and a final geotechnical report.

How deep do you think the piles will be?

Pipe pile and helical pile will continue to be advanced until the required resistance is met. The level of resistance required is determined by the pile’s or helical pile/anchor’s design capacity.

With pin pile, resistance or “refusal” is defined as, “X” seconds for the pile to penetrate one-inch in a given period of time, i.e. 2” pipe pile driven with a 90 lb. jack hammer requires less than one-inch of penetration in 60 seconds of continuous driving.

With helical pile/anchor, there is a direct correlation between resistances to drilling (torque measured in ft.lbs.) to helical capacity. The helical manufacturer’s installation manual includes the mathematical formula to determine appropriate resistance (torque) required for a given design helical capacity.

Can you do the excavation?

Pile King does not do excavation. It is common and recommended for the general contractor, pile contractor and excavation contractor to meet onsite prior to the job start. The purpose of the preconstruction meeting is to form a strategy ensuring the building site is excavated to the proper grade while preserving the pile contractor’s ability to effectively and safely install piles.

Can you do the concrete?

Foundation contractors are the best suited for this type of work.

How long will it take to do the job?

Typically, McDowell Pile King can install piles for a single family residence in about a week.

Is there any vibration?

Ground vibration is minimal when driving small diameter pipe pile. Pile King has collected vibration data on an array of sites and the results confirm vibration measured as a result of driving pile is well below the threshold for damage to adjacent building structures.

Ground vibration for installing helical piles is less than when driving pipe piles.

How noisy will it be?

Pile driving is an inherently noisy process. All onsite personnel are required to wear proper hearing protection. Pile King adheres to the local restrictions for noise restrictions.

Installing helical piles/anchors requires no hammering, just the noise produced by a typical mini-excavator’s diesel engine. No hearing protection required.

What is the difference between a Pipe (Pin) Piling and a Helical Pile/Anchor?

Pipe (Pin) pile are round steel pipe driven into the ground using hydraulic hammers mounted to mini-tracked excavators. Pipe pile typically are utilized where additional compression capacity is required for a buildings foundation. Also, pipe pile or wide flange beams may be driven into the ground to stabilize or retain hill sides. Two-inch diameter pipe pile may be installed using pneumatic jackhammers, larger pile sizes i.e. three/four/six/eight-inch pile are always installed using powerful hydraulic hammers carried on tracked mini-excavators which have been converted to install these piles.

In contrast, helical pile/anchors may have a round shaft or square shaft and are advanced into the ground using hydraulic torque motors usually mounted on a mini-tracked excavator. A helicals’ lead section may contain one or more helical plates or augers allowing the pile to advance into soils. After the lead section is installed subsequent extension pieces are coupled to the lead section. Helical pile/anchors are unique because they provide resistance to both compression and tension loads. Helicals may be installed horizontally as part of a shoring wall system or vertically as part of a foundation system. In limited access conditions helicals may be installed using portable “hand held” torque motors.

What is Piling?

Piling is a generic term used to describe an element placed in the ground as part of a deep foundation system. Piles may be wood, steel or concrete and may be installed in a variety of ways. Piling are used to transfer the building loads from the weak upper soil strata to a more competent and stable soil strata below the existing grade.

How long does it last? Will it need to be replaced at some point?

The longevity of a pile system is influenced by the soil characteristics. A properly designed pile system will last as long the structure has a useful life. When a geotechnical engineer recommends a particular pile system he evaluates the corrosive nature of the onsite soils, the slope stability, depth of the pile and he recommends black or galvanized steel, wood/timber piles or concrete piles.

Is it harmful to the environment?

Piles are often installed at sites designated to be environmentally sensitive. Your site specific geotechnical report should address all specific environmental concerns.

What size is your equipment?

McDowell Pile King installs pipe pile with unique patented equipment designed specifically for installing pipe piles. The Pile King TM machines are basically converted mini-tracked excavators. The most common machine used to install four-inch diameter piles is 6’6” wide and weighs 13,000 lbs. The smallest Pile King TM machine weighs just 3,000 lbs. These pin pile machines are built to operate with in as little as 10’ of overhead clearance.

What type of guarantee do you give?

The pile system is designated by the geotechnical engineer including pile capacity. The structural engineer designates the exact pile locations. The surveyor locates each pile using wood stakes. McDowell Pile King installs the piles per plan under the supervision of the geotechnical engineer.

Piles may be load tested to two-times the pile’s design capacity indicating the installation techniques utilized are sound and the process used to install the test piles are replicated on every production pile.

We offer a warranty for a period of one (1) year from date of substantial completion, on materials and workmanship for piling provided by or installed by McDowell NW Pile King.

Do you level homes?

Minor lifting of the foundation from the pile system has been done in the past, but McDowell Pile King warns against the negative impact associated with this approach. Better results are usually attained by lifting from the crawl space without risk of damage to the foundation.

Do you have references?

References available upon request.

Can I wait to fix it?

An alternative to fixing a sagging or subsiding foundation is to take a wait and see approach. Monitoring a foundation may be a way of delaying the cost to a future date. McDowell Pile King recommends the customer hire a geotechnical engineer to evaluate the homes foundation and the questionable soil which lies beneath. A geotech can evaluate the risk associated with a wait and see approach versus beginning the engineering process; including a geotechnical evaluation including subsurface explorations and then hiring a structural design for design of the foundation repair. For geotechnical or structural engineer referrals please call McDowell Pile King at 425.251.8535.

What caused my settlement?

Weak soils generally are the root cause of foundation subsidence. Piling may be retrofitted to an existing foundation to transfer the weight of the home from the weak upper soils down to the dense or very dense soil well below the existing footing.

Why are we not a general contractor?

McDowell Pile King is a piling subcontractor. We do sometimes contract directly with a homeowner with a defined scope of work.

Are permits required?

Yes, permits are required for all projects requiring piling.

Will insurance cover the cost?

Many home owners’ policies exclude coverage for subsidence or sagging foundations.

What are Manta Rays?

Manta Ray anchors are mechanical anchors made of galvanized ductile iron. They are driven into the ground using jackhammers or concrete breakers mounted on excavators or skid steer loaders.

MANTA RAYs are driven into the ground, not augured or torqued, nor is a hole dug or drilled. There is “no disturbance” or “displacement” of soil. Unlike other anchoring systems, MANTA RAY actually compacts the soil around itself – a clean, safe and simple operation.

The anchors are driven with conventional hydraulic/pneumatic equipment that is readily available worldwide. Once driven to the proper depth, the rod/tendon attached to the anchor is pulled to rotate the anchor into undisturbed soil – like a toggle bolt. This is called “ANCHOR LOCKING” the anchor (using the MANTA RAY Anchor Locker). The anchor is pulled upon to reach the holding capacity required which is measured by a gauge on the “ANCHOR LOCKER.” Each anchor is immediately proof loaded to the exact capacity required. No other system offers this feature.

What are Manta Rays used for?

Stream bed restoration (log tie downs), revetment mats, shoring walls, guide wire anchors, foundation anchors, etc.

How are Manta Rays installed?

The anchors are driven with conventional hydraulic/pneumatic equipment that is readily available worldwide. Once driven to the proper depth, the rod/tendon attached to the anchor is pulled to rotate the anchor into undisturbed soil – like a toggle bolt. This is called “ANCHOR LOCKING” the anchor (using the MANTA RAY Anchor Locker). The anchor is pulled upon to reach the holding capacity required which is measured by a gauge on the “ANCHOR LOCKER.” Each anchor is immediately proof loaded to the exact capacity required. No other system offers this feature.

What are the capacities for different sizes of Manta Rays?

There are seven different model anchors in the Manta Ray line ranging in capacity from 1,000 lbs. to 20,000 lbs working capacity.

How do soil conditions affect the capacities of Manta Rays?

There is a direct correlation with soil density and anchor capacity. Loose weak soils yield a low anchor capacity and dense compacted soils yield a high anchor capacity. The larger the anchor is the more bearing area is developed and the higher the anchor capacity.

Do you rent the equipment for installing, locking and testing the Manta Rays?

Yes. We have rental rates available for specialty drive steel pieces and load testing equipment. Please call for current rates.

Who purchases the Building Permit? Why?

McDowell Pile King does not get involved in the permitting process. Many architects are skilled at navigating your local building department’s permit process.


The advantage of the Pile King™ patented equipment is its very nature of being compact for working on limited access sites and yet able to safely wield powerful hydraulic hammers...


McDowell’s roots in the construction industry goes back to the 40’s working on the Denny regrade in Seattle. We have since specialized in piling and deep foundation systems since the late 60’s...


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