UnderDeck Plan and Product Cost Estimating Form

Here’s how to obtain cost estimates to expand your outdoor living space! By completing the form below and by uploading a couple photos and a rough drawing with measurements of the under side of your deck, FehrMark, Inc. can provide a Free Product Cost Estimate within a few working days. You buy the exact quantity of UnderDeck components needed, not carton quantities, so you won’t end up with extra expense and wasted product.

Important: You may want to install a standard water gutter system at the edge of your deck to divert the water away from your home. NOTE: THE UNDERDECK SYSTEM PURCHASED FROM FEHRMARK INC. DOES NOT INCLUDE THE OPTIONAL RAIN GUTTER OR DOWNSPOUTS. The rain gutter and downspouts can be purchased at most local building supply stores. Follow the installation methods provided by the gutter manufacturer. Note: The UnderDeck outdoor ceiling system is cut slightly shorter if you choose to use water gutters.

UnderDeck is easily installed by a handy Do-It-Yourselfer or a local carpenter. You may download the installation instructions here. The instructions include the list of tools and supplies required to install UnderDeck. You can decide if you want to install-it-yourself or hire someone after you’ve reviewed our instruction guide and watched our online videos.

Below are three drawings showing standard deck configurations. Use the letter key in the drawing to complete the Estimating Form below. Your number of deck joists and dimensions may be different than the examples shown below, but you should be able to understand what we are looking for from you to create an estimate. If not, contact us.

Also, if your deck configuration is different than one shown, we will be glad to help you. Contact FehrMark, Inc. at 1.888.353.3347 or email Our fax number is 570.739.4424.

Product Cost Estimate Form

Are you a:




Deck Prep

The ledger board is the board attached to your building and from which your deck is hung. It may be painted, or you may order and install Ledger Wrap. Would you like us to include Ledger Wrap as an option in the quote? *YesNo

Check for any obstructions such as blocking, bracing, posts, or beams which may require some modification or planning before installing. These modifications should be included in your total project cost estimate. Click here to view or download the detailed installation drawings. If you have questions, you may call FehrMark at 1.888.353.3347 or email

UnderDeck System Estimate

Refer to the Steps below and Drawings above.
IMPORTANT: Please be sure to fill out the form completely, or the form will not be sent. All fields with the red asterisk must be completed.

  1. Determine your color preference and deck size:*
    The product is available in WhiteTan

  2. What is your deck depth (from building to outside edge of deck) in inches? *
  3. What is your deck width in inches?*
  4. Determine the number of Joist Rails required:
    Number of joist spaces (C) *
    Joist length (E) in inches *
    x 2 ÷ 37 =
    Number of Joist Rails required
  5. Determine the number of Collector Panels needed by counting the number of Joist Spaces. (D).
    Quantity *
  6. What is your Joist Spacing (center-on-center) in inches? * 121624
  7. Determine the number of Joist Gutters (B) (This quantity will be equal to the number of inside joists) *
  8. Does your deck use any Double or Triple Joists? * YesNo
    Double and Triple Joists require custom pieces. If you indicated Yes, we will contact you by email or phone.
  9. Determine the number of Boundary Gutters (A)This quantity will be equal to the number of edge joists. (There are usually two edge joists on a typical rectangular deck.)*

  10. IMPORTANT NOTE: We will calculate other required components not listed above, based upon the information you provide above. These required components include:
    • Water Diverters – One per Joist Space

    • 5" Weather Strips – One for each Joist and Boundary Gutter

    • Nails – Three for each Water Diverter; Four for each Joist Rail
  11. If your deck has unusual shapes or dimensions, call or email us. We’ll be glad to help you provide the information we need to provide an accurate measurement.
ex: 000 000-0000


UPLOAD YOUR DECK PHOTO(s) HERE: Note: While not required, photos of your under deck can be very helpful to estimate your deck. EACH PHOTO SHOULD BE LESS THAN 2 Mb TO FACILITATE UPLOAD. You do not need to send 3 photos, but different photo angles of the area under your deck may be helpful. If you would like to provide a rough sketch of your deck joists, and you can scan the drawing, and it may also be sent through our form. You may also fax the drawing to us at 570.739.4424.

If you want to send additional photos, please email them directly to


Upload photo #2 here:
Upload photo #3 here:



Please be sure to fill out the form completely, or the form will not be sent. All fields with the red asterisk must be completed.

To send, click the button below, but please DO NOT close the browser window until you get the message that your form has been sent. Thank you for the opportunity to provide this cost estimate!