LaHouse Building Systems and Features (Mid Section)

Claudette Reichel  |  12/18/2008 1:02:20 AM

Adding Concrete to stemwall

Hurricane strapping

sill gasket

Mid Section of House
(Living Area)

Conventional wood framing with high-performance details:

Wall Framing:

· Laminated strand lumber (LSL) 2x4 studs spaced 16 in. o.c.

o Straight, precise & stronger; great for high ceilings and “balloon framing” of gable end walls (foundation to roof)

o No warped rejects, so less waste; efficient use of local natural wood resource

o Made with borates for termite resistance

· Engineered wood I-beam ceiling joists

o Straight, uniform; minimize 2nd floor squeaks

o High strength, stiffness, very long spans

o Alternative to 2x12 lumber from old growth forests

o Ends sprayed with borate treatment for termite protection

· 15/32 in. plywood wall sheathing

o factory borate treated for termite protection of structure

Roof framing:

· Borate treated 2x8 in. rafters, spaced 24 in. o.c.

o Ridge beam and collar ties; designed for semi-conditioned, accessible attic (see exhibit room)

o Supports weight of roof tile, space for R-30 insulation

· 19/32 in. borate treated plywood decking (termite protection)

o grid marked for faster, precise installation

· Attic knee walls detailed same as walls


Energy-saving building details:

Passive solar (sun control):

· Ventilated roof tile – elevated on battens, vented birdstops

· Overhangs, porch for every season; cross ventilation design

· House, window oriented for max. S & N exposure, min. E & W

· South overhang shades summer sun, admits winter sun

· Energy Star, low-e windows, doors (SHGC < 0.4)

Tight Construction and Continuous Insulation:

· Walls: Continuous R-5 exterior rigid foam boards in addition to R-13 wall cavity insulation

o Back wall: foil-faced Iso board is also radiant barrier behind cementious siding (installed with air space)

o Front wall: drainable EIFS with borate treated EPS foam

o Both walls: sprayed cellulose insulation between studs provides full coverage, no voids or compression

· contains borates for fire and termite resistance

· made from recycled newspaper

· Band between levels insulated, sealed with spray foam

· Penetrations foam sealed

· Attic: Unvented, cathedralized, semi-air conditioned attic

o R-30 airtight spray foam under roof, not attic floor

· roof-wall intersection blocked and foam sealed

o Ducts, air handler within conditioned space (no gas)

· Prevents typical 30% A/C/heat loss (in vented attics)

· Allows downsized A/C – can save enough $ to offset cost of energy upgrades (net zero cost)

o Clean, conditioned storage space

HVAC and HW systems:

· Geothermal heat pump (serves east half of house)

o Highest efficiency – EER 21-24, dual capacity

o Cools & heats via closed loop, exhibited 2 ways:

§ in ground (in 200 ft. deep vertical bore hole)

§ in pond (via stainless steel plate heat exchanger)

o No backup heat source needed

o Ozone friendly 410A refrigerant

· Ductwork within conditioned space – short, efficient layout

o Rigid trunk, sealed with mastic (not duct tape)

o No need to run to exterior walls with low-e windows

· Hot water reclaim system

o Free hot water when geothermal running

o With high efficiency electric water heater tank

· Fresh air intake with flow controller for controlled, filtered ventilation needed for healthy air quality

· Whole house dehumidifier for optimal healthy RH <50%

o independent humidistat

o maintain RH even when cooling not needed

o draws air from interior, delivers to HVAC supply ducts

· In-line kitchen exhaust system

o Quiet, powerful removal of cooking steam, odors

· Direct vent gas fireplace – sealed combustion

o Fresh air duct, not indoor air, feeds fire – saves energy

o No backdrafting – protects indoor air quality

Weather Barriers:

· Sill gasket (2 types) seals bottom plate to slab – saves energy

· Back wall: foil-faced Iso foam board with taped seams

o drainage plane, vapor barrier, air barrier & radiant barrier

· Front wall: crinkled housewrap (drainage plane) behind EPS foam board (vapor retarder) & synthetic stucco (air barrier)

· Window flashing & installation to drain water leaks to outside

o Sill backdam, adhesive flashing tape + corner guards

o all layered shingle fashion

o no tape on bottom flange so leaks drain to exterior

Fortified features (to resist 130 mph wind & flood damage):

· 15/32 in. plywood on exterior walls, close nailing pattern

· Connectors form continuous load path -- ties roof to foundation

o Anchor bolts w/ 3 in. washers hold sole plate to slab

o Hurricane hardware connects each stud to sole plates

o Metal straps tie 1st story to attic kneewalls

o Metal twist straps tie porch columns, headers to roof rafters; hurricane clips connect kneewalls to rafters

o Roof ridge straps connect front to back rafters

· Roof: 19/32 in. plywood roof decking

o ring shank nails, 6 in. spacing, 4 in. at gable end

o Peel and stick membrane roof underlayment

o Tile roofing – 2 screws/tile + clips on first course

· Elevated slab cap foundation (see details in west wing)

o Assorted impact rated window, door protections


 

 

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