Hot-Water Radiant Floor Heating Methods

Hot-Water Radiant Floor Heating Methods

hot-water radiant floor heating methods

Hydronic (hot water) radiant floor heating is mostly associated to thick concrete slabs. But radiant floor heating can also involve thin slabs and metal plates.

Three methods

In fact, modern hot water radiant heating comprises three basic methods. the common and traditional 1) slab-on-grand method, based in thick concrete slabs, but also the 2) thin-slab method and the 3) plate-type method (involving heat-transfer aluminum plates).

All rely on tubing circuits laid underneath the floor covering; and all receive heated water from a boiler, which circulates through the circuits before returning to the boiler to reheat.

Plate-type radiant heating (image at right) is the best choice for retrofit situations, namely when framing strength isn’t enough to support a thin-slab, or when raising the level of the floor isn’t feasible.

Things that matter

Though simple in their basics, the success of any radiant heating system relies on several important rules and details. Implementing a radiant floor heating requires proper planning. adequate layout for the radiant tubing and proper insulation to avoid under-floor heat loss

Planning

Whatever you choice about the type of radiant floor heating, planning is crucial.

Planning involves drawing the layout of all the tubing circuits (often with a CAD program) and the manifold stations, where each tubing circuit begins and ends. Ideally that should be done on a room-by-room basis, to take into account the individual heating needs.

Planning involves also details about the insulation of the floor, the floor thickness or its load-baring.

Insulation

Adequate insulation is critical in any radiant floor heating system. Thats the only way of reducing heat loss to adjacent areas. The exact materials and procedures vary with the type of radiant system.

In the slab-on-grade system the sub-slab insulation is typically provided by extruded-polystyrene. and involves not only the areas under the slab but also any exposed edge.

In the thin-slab and plate-type systems for wood-frame floors, rigid foams and fiberglass batts are good choices (the insulation levels vary according to the type of space above the floor: heated spaces, basements, crawlspaces).

Slab-on-grade

The slab-on-grade floor system is the most common and the most economical for radiant heating; whenever a concrete is already planned, the cost of floor heating is basically the cost of installing the tubing in the concrete slab and the cost of slab insulation.

As mentioned earlier, the slab should be carefully insulated from below and from the foundation walls.

Thin-slab

Thin-slab radiant floor-heating systems are a good alternative to the more common slab-on-grade systems in wood frame floors .

The most common approach to install this system is to fasten tubing to the subfloor and to cover it with a thin layer (up to 1,5 inches/2,5 cm) of poured underlayment. Poured gypsum-based underlayments and poured gypsum-based underlayments are the most common options.

Prices per square foot are somewhere between those of slab-on-grade and plate-type radiant floor (often above $5 per square foot).

Plate-type radiant floor

Plate-type radiant floor systems rely on aluminum plates to transfer heat into the floor; they wrap partially around tubing. The plates (and the tubing) can be installed below (the more common option) or above plywood subflooring.

This system is the best option for retrofit applications. It doesn’t add a significant weight to the floor and doesn’t disturb the existing flooring. But it requires a closer net of tube spacing and higher water temperatures than slab-type systems.

Tubing

Copper tubing is a thing of the past. and a poor choice compared to new PEX (polyethylene), PEX composite and polybutylene tubing. Contrary to these plastic tubing, copper tubing expands at rates that can compromise the integrity of the slabs where they are embedded.

Coverings

Do not use floor coverings with high insulation values. They will aggravate the already slow response time of radiant floor heating to thermostat changes. See: Radiant Heating Floor Coverings .

hot-water radiant floor heating methods

Hydronic (hot water) radiant floor heating is mostly associated to thick concrete slabs. But radiant floor heating can also involve thin slabs and metal plates.

Three methods

In fact, modern hot water radiant heating comprises three basic methods. the common and traditional 1) slab-on-grand method, based in thick concrete slabs, but also the 2) thin-slab method and the 3) plate-type method (involving heat-transfer aluminum plates).

All rely on tubing circuits laid underneath the floor covering; and all receive heated water from a boiler, which circulates through the circuits before returning to the boiler to reheat.

Plate-type radiant heating (image at right) is the best choice for retrofit situations, namely when framing strength isn’t enough to support a thin-slab, or when raising the level of the floor isn’t feasible.

Things that matter

Though simple in their basics, the success of any radiant heating system relies on several important rules and details. Implementing a radiant floor heating requires proper planning. adequate layout for the radiant tubing and proper insulation to avoid under-floor heat loss

Planning

Whatever you choice about the type of radiant floor heating, planning is crucial.

Planning involves drawing the layout of all the tubing circuits (often with a CAD program) and the manifold stations, where each tubing circuit begins and ends. Ideally that should be done on a room-by-room basis, to take into account the individual heating needs.

Planning involves also details about the insulation of the floor, the floor thickness or its load-baring.

Insulation

Adequate insulation is critical in any radiant floor heating system. Thats the only way of reducing heat loss to adjacent areas. The exact materials and procedures vary with the type of radiant system.

In the slab-on-grade system the sub-slab insulation is typically provided by extruded-polystyrene. and involves not only the areas under the slab but also any exposed edge.

In the thin-slab and plate-type systems for wood-frame floors, rigid foams and fiberglass batts are good choices (the insulation levels vary according to the type of space above the floor: heated spaces, basements, crawlspaces).

Slab-on-grade

The slab-on-grade floor system is the most common and the most economical for radiant heating; whenever a concrete is already planned, the cost of floor heating is basically the cost of installing the tubing in the concrete slab and the cost of slab insulation.

As mentioned earlier, the slab should be carefully insulated from below and from the foundation walls.

Thin-slab

Thin-slab radiant floor-heating systems are a good alternative to the more common slab-on-grade systems in wood frame floors .

The most common approach to install this system is to fasten tubing to the subfloor and to cover it with a thin layer (up to 1,5 inches/2,5 cm) of poured underlayment. Poured gypsum-based underlayments and poured gypsum-based underlayments are the most common options.

Prices per square foot are somewhere between those of slab-on-grade and plate-type radiant floor (often above $5 per square foot).

Plate-type radiant floor

Plate-type radiant floor systems rely on aluminum plates to transfer heat into the floor; they wrap partially around tubing. The plates (and the tubing) can be installed below (the more common option) or above plywood subflooring.

This system is the best option for retrofit applications. It doesn’t add a significant weight to the floor and doesn’t disturb the existing flooring. But it requires a closer net of tube spacing and higher water temperatures than slab-type systems.

Tubing

Copper tubing is a thing of the past. and a poor choice compared to new PEX (polyethylene), PEX composite and polybutylene tubing. Contrary to these plastic tubing, copper tubing expands at rates that can compromise the integrity of the slabs where they are embedded.

Coverings

Do not use floor coverings with high insulation values. They will aggravate the already slow response time of radiant floor heating to thermostat changes. See: Radiant Heating Floor Coverings .

hot-water radiant floor heating methods

Hydronic (hot water) radiant floor heating is mostly associated to thick concrete slabs. But radiant floor heating can also involve thin slabs and metal plates.

Three methods

In fact, modern hot water radiant heating comprises three basic methods. the common and traditional 1) slab-on-grand method, based in thick concrete slabs, but also the 2) thin-slab method and the 3) plate-type method (involving heat-transfer aluminum plates).

All rely on tubing circuits laid underneath the floor covering; and all receive heated water from a boiler, which circulates through the circuits before returning to the boiler to reheat.

Plate-type radiant heating (image at right) is the best choice for retrofit situations, namely when framing strength isn’t enough to support a thin-slab, or when raising the level of the floor isn’t feasible.

Things that matter

Though simple in their basics, the success of any radiant heating system relies on several important rules and details. Implementing a radiant floor heating requires proper planning. adequate layout for the radiant tubing and proper insulation to avoid under-floor heat loss

Planning

Whatever you choice about the type of radiant floor heating, planning is crucial.

Planning involves drawing the layout of all the tubing circuits (often with a CAD program) and the manifold stations, where each tubing circuit begins and ends. Ideally that should be done on a room-by-room basis, to take into account the individual heating needs.

Planning involves also details about the insulation of the floor, the floor thickness or its load-baring.

Insulation

Adequate insulation is critical in any radiant floor heating system. Thats the only way of reducing heat loss to adjacent areas. The exact materials and procedures vary with the type of radiant system.

In the slab-on-grade system the sub-slab insulation is typically provided by extruded-polystyrene. and involves not only the areas under the slab but also any exposed edge.

In the thin-slab and plate-type systems for wood-frame floors, rigid foams and fiberglass batts are good choices (the insulation levels vary according to the type of space above the floor: heated spaces, basements, crawlspaces).

Slab-on-grade

The slab-on-grade floor system is the most common and the most economical for radiant heating; whenever a concrete is already planned, the cost of floor heating is basically the cost of installing the tubing in the concrete slab and the cost of slab insulation.

As mentioned earlier, the slab should be carefully insulated from below and from the foundation walls.

Thin-slab

Thin-slab radiant floor-heating systems are a good alternative to the more common slab-on-grade systems in wood frame floors .

The most common approach to install this system is to fasten tubing to the subfloor and to cover it with a thin layer (up to 1,5 inches/2,5 cm) of poured underlayment. Poured gypsum-based underlayments and poured gypsum-based underlayments are the most common options.

Prices per square foot are somewhere between those of slab-on-grade and plate-type radiant floor (often above $5 per square foot).

Plate-type radiant floor

Plate-type radiant floor systems rely on aluminum plates to transfer heat into the floor; they wrap partially around tubing. The plates (and the tubing) can be installed below (the more common option) or above plywood subflooring.

This system is the best option for retrofit applications. It doesn’t add a significant weight to the floor and doesn’t disturb the existing flooring. But it requires a closer net of tube spacing and higher water temperatures than slab-type systems.

Tubing

Copper tubing is a thing of the past. and a poor choice compared to new PEX (polyethylene), PEX composite and polybutylene tubing. Contrary to these plastic tubing, copper tubing expands at rates that can compromise the integrity of the slabs where they are embedded.

Coverings

Do not use floor coverings with high insulation values. They will aggravate the already slow response time of radiant floor heating to thermostat changes. See: Radiant Heating Floor Coverings .


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