Install Instructions

IM-PR 566442 1114 (Design Manual)

192

Step 9: Insulation

Insulation should always be used in a staple-up radiant installation. Ideally there should be a 1" to 2"

air gap in between the insulation and the Traks/plates.

However, the air gap should only be left if that space is considered a dead air space (absolutely no air

current through it, whether it be from an outside wall, from below or through holes in the subfloor).

To create a dead air space, begin by insulating the outside ends of the joist bays with a separate piece of

insulation (insulation blocking) between the top of the foundation and the bottom of the subfloor to keep

cold air from entering through sills and outside walls.

Any air current through this space will decrease the performance of the system and the insulation. By

insulating outside walls, sealing any large gaps in the subfloor and ensuring that the insulation is tight

against the joist, this will create a situation where the air gap is beneficial to the performance of the

system.

If a dead air space is unable to be achieved, then the insulation should be pushed up lightly against

the Traks/plates.

Fr om Decoiler

To Manifold

Inside Wall

Outside Wall

Insulation Blocking

NOTE: When using expanding foam insulation on and around the PEX tubing, please contact the

manufacturer of the foam or Viega for PEX compatibility issues. Some foams may cause excessive heat if

installed improperly. This excessive heat may cause damage to the PEX.