SKIMFLOW® LP with hybrid gypsum hydraulic cement technology is an innovative self leveling underlayment designed to facilitate ramping (1/4” in 12”) or very flat floors. SKIMFLOW LP is designed to address out of level or old damaged floors in residential, commercial, institutional and renovation environments. SKIMFLOW LP dries to a smooth hard surface that facilitates rapid application of flooring goods in as little as 16 hours. SKIMFLOW LPs exceptional volume stability and bonding characteristics facilitate application in light foot and commercial traffic areas without requiring mechanical preparation of the substrate. Suitable for application over clean, sound substrates including concrete, gypsum, wood, corrugated steel deck LP may also be used over well bonded adhesives. LP is optimized for installation from 1/4” to 3” NEAT in a single lift, in climate controlled interior environments. SKIMFLOW LP offers compressive strengths exceeding 4100 psi (28 days) and is compatible with some sound attenuation systems.

Features and Benefits




Preparation and Application



Reference the floor covering and adhesive manufacturers documentation to verify suitability of SKIMFLOW LP as a subfloor for the flooring system (any adhesive used for concrete is generally suitable for LP). Follow the directions of the flooring and adhesive manufacturer to determine the maximum allowable moisture content (RH) or transmission of the substrate. If the moisture content (ASTM F-2170) or moisture vapor transmission rate (ASTM F-1869) of the substrate exceeds the requirements of the flooring system, utilize an approved 100% epoxy moisture vapor mitigator prior to installation of the SKIMFLOW LP.

Honor all moving joints. Complete crack and substrate repairs prior to installation. Consult an engineer for required joints and crack repairs prior to installation. Contact Technical Services for required surface preparation on installations that will be exposed to high rolling loads or high point loads.

Maintain a minimum of 50oF during the pour and for 72 hours after the pour. Acclimate the material to a minimum of 55ºF prior to mixing. To maximize flowability and working time, utilize cool water when temperatures exceed 85ºF.

For installation over hydronic heating systems utilize a minimum of 1.5” of material, with 3⁄4” of material above the hydronic system. SKIMFLOW LP is compatible with and accepts the direct application of, urethane, moisture cure and other typical floor covering adhesives.

SKIMFLOW LP can be applied in two lifts to a maximum depth of 3” NEAT. It is recommended clean, washed and SSD (saturate surface dry) 1/4 – 3/8” pea gravel is utilized in areas deeper than 2”. Applications deeper than 3” must be extended with aggregate. Extend LP up 50% (by weight – 25 lbs pea gravel per 50 lbs LP). Ensure pea gravel is thoroughly mixed in (encapsulated) by the LP.


All Substrates must be sound, clean, dry and free of contaminants (oil, dirt, laitance etc.) that may interfere with adhesion. Areas of the floor that do not exhibit a tensile pull strength greater than 100 psi are not suitable and must be mechanically removed to a sound, stable base and subsequently repaired prior to application of SKIMFLOW LP. Do not use solvents, acids, chemical adhesive removers to prepare the substrate. All bond breaking substances (cure residues, excess salts from silicates etc.) must be removed prior to priming.

Completely vacuum all dust and debris from the substrate prior to priming with designated Dependable Primer A. Gypsum substrates must exhibit a sound surface, be free from dust and surface weakness prior to application of the primer.

Non-soluble adhesives must be scraped to a well bonded residue. Water soluble adhesives must be removed mechanically to the substrate. Verify type of adhesive prior to mechanical removal to ensure adhesive containing asbestos is not introduced into the environment. Follow all local, state and federal laws for removal and disposal of adhesive or flooring materials containing asbestos. SKIMFLOW LP is not for use as a suitable means to encapsulate residue of hazardous materials.

Wood floors must satisfy local building codes, utilize exterior grade plywood, suitable OSB or other resistant to water, and be free from deflection. The wood must be free of contaminants (oils, wax, dirt etc.) that could function as bond breaker prior to application of the primer. Wood floors that exhibit extreme deflection may require the use of reinforcing lath, contact technical support for details.

Substrate Priming

Prime properly prepared substrate with an PRIMER A or approved alternate primer prior to the application of LP, Prime properly prepared porous (concrete) and non-porous substrates (adhesive residue, epoxy terrazzo, ceramic tile etc.) with approved primer by soft tipped broom (porous) or 3/8” nap roller (non-porous). Carefully read Primer data sheet to ENSURE Primer is utilized diluted (porous substrates) or undiluted (non-porous substrates) per given substrate.

SKIMFLOW LP is very flowable and will ow through any exposed voids. To avoid material ow in undesirable areas, seal voids or penetrations with a rapid setting patch or expanding foam. LP has tremendous bonding properties, place tape or bond breaker on vertical surfaces that will contact the SKIMFLOW LP. Provide a barrier between SKIMFLOW LP and metallic construction (e.g. heating pipes). When applying SKIMFLOW LP on wood substrates, utilize reinforcing lath stapled to the wood floor after priming.


Water: 3.75 – 4.5 US Qts (3.5 – 4.25 L) per 50 lbs (22.7 kg)
Mix Time: 2.5 minutes with minimum 650 rpm drill or through pump.

Over-watering and/or under mixing (failing to generate adequate shear) will result in lower ultimate compressive strengths.

Add designated clean, potable water to a clean mixing barrel, add the powder and mix at the designated speed for 2.5 minutes. Ensure all material is homogenous, and no dry lumps or unmixed material is at the bottom of the mix. During mixing, keep the paddle below the surface of the material to reduce introduction of excess air into the mix. Once mixed, pour onto the substrate immediately to maximize material ow and placement time.


SKIMFLOW LP may be mixed and/or pumped with most standard batch or inline mixing/pumping equipment. Contact Dependable Technical services for pump questions.

Material Application

Immediately after mixing is complete pour the mix on the substrate, rake to the required depth and smooth using appropriate tools (smoother or porcupine roller). When placing mixed material, maintain a wet edge, always pouring back into the leading edge of the previous placement.

Drying Time

Do not used forced air to assist in drying SKIMFLOW LP, but do provide for adequate ventilation and circulation of air. SKIMFLOW LP generally hardens to accept light foot traffic 3 – 4 hours after placement. Avoid construction traffic for a minimum of 16 – 24 hours (temperature dependent).

LP is self drying, do not wet cure or use curing or sealing compounds. To facilitate drying, ensure rooms where LP is installed have air circulation. Do not introduce heavy air ow to the surface of LP until after 16-24 hours of drying. Temperature, humidity and air ow will impact drying time. The use of a moisture meter is recommended to verify readiness for flooring. Multiple areas should be surveyed to ensure dryness throughout. Use of a Delmhorst G-79 and a reading of 5% moisture content or lower, or a GE® Protimeter moisture meter such as the Aquant. In the RF (Radio Frequency) mode a ready of 180 or lower indicates suitable dryness for any floor covering.

General drying guidelines assuming ambient temps of 70oF with air circulation (Cooler temperatures and/or high humidity will increase drying times);

Breathable Flooring Systems

Depth: Dry time required before installing flooring

0 – 1”: 16 hours (next day)

1 – 2”: 36 hours (1.5 days)

2 – 3”: 60 hours (2.5 days)

Non-Breathable/Impervious Flooring Systems

Depth: Dry time required before installing flooring

0 – 1/2”: 24 hours

1/2 – 1”: 48 hours

>1”: 48 hours plus 36 hours for each additional 1/2″

When LP may be subject to water exposure, prime with an acrylic primer, such as Primer A). Follow primer instructions.

General Guidelines

• For interior use only
• Install between 50– 90ºF
• For installation in enclosed, climate controlled buildings
• Keep dry and above 50ºF for 72 hours after installation
• Avoid exposure to regular trade traffic for 24 hours after application
• Not for use as a permanent wear surface.
• Installation must conform to applicable local, state and federal building codes.
• Do not use where hydrostatic pressure is present or moisture emissions exceeds level permitted for an installed floor covering SKIMFLOW LP Underlayment can tolerate any amount of moisture from a concrete slab so long as all of the moisture from the slab will escape past the floor covering. If the floor covering’s moisture permeability does not meet or exceed the moisture content of the slab, Dependable recommends moisture remediation. Use Dependable’s Vaporseal HM, or an approved alternative, to remediate moisture in concrete, consult the Vaporseal HM data sheet, or call technical services, for more details.


Store in cool and dry conditions, out of direct sunlight with pallets wrapped in original shrink wrap.

Clean-up and Disposal

Wash hands and tools with water before the material hardens, or within 10 minutes of material contact to ensure easiest removal. Cured material must be removed mechanically. Dispose waste or excess material in accordance with all local, state and federal regulations. Hardened material is generally considered construction waste.


Additional Information