Rain on this project caused the complete failure of all cardboard column forms.

TIPS TO PREVENT WATER DAMAGE TO CARDBOARD COLUMN FORMS

Cardboard is hygroscopic, meaning that it adsorbs moisture from its surroundings. This moisture reduces the structural strength of the cellulose fibers dramatically and can lead to column failure, as shown in the picture to the right.

"Moisture or wetness damaged cardboard suffers depreciation due to linear distortion, torsion phenomena, changes in smoothness and color, reduction in mechanical tensile strength and  waviness. This damage is irreversible, since drying leads to warping due to inner tensions resulting from non-uniform distribution of the moisture within the cardboard."

These 12' tubes have been wrapped with poly to prevent water damage both during transport and on the jobsite.

The following steps must be taken to prevent cardboard tube failure due to moisture:

1. Store cardboard tubes in a dry (low humidity) environment until the day of the pour. Never leave cardboard on a jobsite where it can be exposed to moisture and humidity.

2. Move the cardboard tubes to the jobsite on the morning of the concrete pour to minimize potential for moisture damage. If possible, arrive at least two hours early to set up tubes in advance of concrete.

3. An enclosed vehicle must be used to transport cardboard tubes. If this is not possible, carefully wrap to tubes with 4 mil poly. To prevent wind damage to the poly in transit, tightly tape the poly around the tubes with 2" tape as shown.

Garbage bags are the perfect solution to prevent water damage to the top of the cardboard tube.

4. Install each tube and brace appropriately. Garbage bags must be purchased and then placed over the top to ensure rain does not enter the tube and weaken it. Be sure to pull the bag over the tube prior to attaching the tube to the bracing. If windy, tightly tape the garbage bag around the cardboard tube and bracing to prevent wind damage to the garbage bag.

5. Use a utility knife to cut the garbage bag from the top of each tube immediately before placing concrete.

There is an alternative to cardboard tubes: Fast-Tube™. Fast-Tube™ is poly-based and cannot be damaged by moisture. Fast-Tube™ can be setup weeks in advance because it can be left out in the rain. Click here for more information.

Let's all sing together now:

"It's raining, it's pouring
And Fast-Tube's still performing"
(Second verse, same as the first.)