Other Products for Hydrotech Assemblies

Other Products for Hydrotech Assemblies

STYROFOAM® Insulation

Dow's STYROFOAM Insulation is an extruded polystyrene insulation ideal for exposed wet applications, and has the following characteristics...

  • Thermal stability..."R" value of 5 per inch
  • Excellent for exposed applications...Moisture resistant & Dimensionally stable
  • High-compressive strength...25, 40, 60 or 100 psi (to fit the use)
  • Environmentally friendly...CFC free & Recyclable

Dow Chemical is the inventor of the Protected Membrane Roof (PMR) assembly, and in the 1970’s Dow and Hydrotech started marketing the first PMR configuration that could be offered as a single source warranty. For over 30 years, only STYROFOAM insulation has been placed over MM6125. As the market accepted the PMR concept, Hydrotech was again the first to offer innovation – the first PMR warranty to include removal and replacement of the overburden.

Hydrodrain® - Drainage Solutions

Water management is a critical issue in the design and construction of a structure. Without proper drainage, severe structural damage could occur. In below grade structures, proper drainage will reduce hydrostatic pressure by channeling water away from the structure. For horizontal applications, in particular dead level or low slope structures, proper drainage can provide an avenue for the water to flow to the drains between the membrane and topping materials. For between slab applications, it can decrease the risk of possible freeze thaw damage to the wearing surface.

Millions of square feet of Hydrodrain and Thermaflo drainage composites have been specified by architects and engineers nationwide for over 25 years. Hydrotech offers a wide variety of cost effective, state-of-the-art drainage media. Typical uses include plaza decks, roof gardens, planters, retaining walls, and foundation walls.      

Hydrodrain 300, 302, 1000 and AL are composite drainage products consisting of a three-dimensional geonet, crush-proof drainage core and a non-woven, needle punched filter fabric. There are several variations of this product to meet particular project requirements. These products are acceptable in both horizontal and vertical applications, but are considered ideal in horizontal installations where a high compressive strength is desired.

Hydrodrain 400, 420, 700 and 990 are composite drainage products consisting of three-dimensional "dimple" type polyethylene core with a non-woven, filter fabric (Hydrodrain 400 and 420 are needle punched). There are several variations of this product to meet particular project requirements. These products are acceptable in both horizontal and vertical applications, but are typically used in vertical installations (foundation walls, planters, etc.) where it's high flow rate is a plus.

Hydroguard® - Hydrotech's Lightweight PMR.

Hydroguard provides both insulation and lightweight ballasting for PMR assemblies. Composed of 2 ft. x 4 ft. STYROFOAM® panels topped with latex modified concrete and tongue and groove edges along the long sides allow each board to be interlocked during installation, creating a continuous layer of thermal protection. Hydroguard acts as a durable barrier, protecting the roofing membrane from temperature extremes and mechanical abuse. Lightweight and easy to install, Hydroguard is ideal for flat roof applications where the use of stone ballast is not practical. Advantages...

  • Provides protection to MM6125® from environmental extremes and construction and maintenance traffic.
  • Eliminates condensation problems by insulating the roof assembly and keeping the dew point above the roof membrane.
  • Smooth, attractive surface is resistant to thermal shock, sun, hail and vandalism.
  • CFC free and reusable.


  • Hydroguard is designed to accept light foot traffic. In applications where excessive foot or construction traffic is anticipated, walkway pads of concrete pavers must be used.
  • Depending on the site and wind conditions, additional securement may be required.
  • Panels should be shielded from direct sunlight until installation.


Hydroguard is topped with a nominal 3/8 thick surface and weighs on average 4.5 pounds per square foot. For applications where additional protection is required, Hydroguard is also available with a thicker concrete topping. Heavy Hydroguard has a 15/16 inch thick surface and weighs approximately 11 pounds per square foot. Hydroguard comes in six attractive colors, including natural gray (standard), white, red, green, light brown and tan.

Physical Properties...

Hydroguard Physical Properties ChartShow




Extruded Polystyrene

Type VI

ASTM C 578

Latex Modified Concrete Face




3/8" thick



15/16" thick


Finished Overall Dimension:

24" wide by 48" long/p>



2.375: thick (2" foam)



3.375" thick (3" foam)



2.938" thick (2" foam)



3.938" thick (3" foam)






4.5 lbs./sq/ft.



11 lbs./sq/ft.


R Value @75 °F mean temp

5 per inch of foam

ASTM C 518

Water Absorption

<0.1% by volume (max.)

ASTM C 272

Water Vapor Permeance

0.8 perm (max.)



750 cycles

ASTM C 666 "B"

Compressive Strength (foam)

40 lbs./sq. inch

ASTM D 1621

Steel Ball Impact Test

Slight Indentation

FM 4470

Point Loading (1"x1"):




450 lbs./sq. ft.



1300 lbs./sq. ft.


ThermaFlo® - Protection, Drainage & Insulation

Thermaflo combines the excellent thermal protection of STYROFOAM® insulation, superior drainage capability and protection to the waterproofing membrane - all in a single product. This 3 in 1, multi-purpose product is particularly well suited to below grade vertical foundation walls. Thermaflo panels are 2 ft. x 8 ft. Dow STYROFOAM® extruded polystyrene foam insulation with horizontal and vertical drainage channels on one side, covered by spun-bonded polyester fabric. Tongue and groove edges along all sides allow each board to be interlocked during installation, creating a continuous thermal and drainage barrier.

The advantage of Thermaflo on a foundation wall is that it cuts labor in half, when compared to the installation of a separate protection layer and drainage composite. The thermal protection is an added benefit.



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