LaHouse Building Systems and Features (West Wing)

Claudette Reichel  |  12/18/2008 1:34:39 AM

continuous concrete footings

easy riser stair system

Cellulose insulation

West Wing (Bedrooms, bathrooms, upstairs offices)

Advanced Framing (Optimum Value Engineered):

  • 2x6, 24 in. o.c. spacing, aligned stack framing
  • 3-stud corners and t-joints that allow insulation
  • drywall clips instead of extra wood
  • Energy-efficient (R-19 without rigid foam, fewer gaps)
  • Strong, with less lumber
  • borate pressure treated 2x6 southern pine – local resource, termite resistant
  • similar in cost to conventional framing, yet outperforms
  • fewer pieces, less labor
  • easier hurricane connections (studs, joists, rafters align)
  • LSL band joists between levels – strong, straight, borate treated

Interior framing materials:

  • Finger-joint 2x4’s southern pine for interior partitions
  • Straight, no rejects, so less waste
  • Efficient use of local wood resource
  • Trimmable open web floor trusses with finger joints
  • Allows jobsite adjustment
  • Long spans
  • Openings for wiring, ducts, etc.
  •  Engineered stair risers
  • stronger, premarked, requires less skill and time
  • uses 2x6 stringer, instead of 2x12

Sheathings

  • Grid marked, foil faced OSB roof decking
  • Radiant barrier keeps vented attic cooler
  • Front: Borate treated plywood
  • termite resistant with standard nails
  • Back: Copper treated OSB (need corrosion resistant fasteners)
  • Highly resistant to termites, mold, moisture, decay
  • Side (MBa): Copper treated, foil faced OSB, seams taped
  • Vapor barrier, radiant barrier, drainage plane all in one
  • Vapor barrier best practice with brick veneer to resist heat driven moisture into wall

Weather Barriers

  • Front: 2 layers behind 3-coat stucco for drainage plane
  • crinkled housewrap creates drainage gaps
  • building paper layer bonds to stucco (vapor retarder)
  • stucco provides air barrier, not moisture barrier
  • Back: housewrap and rain screen behind siding
  • vapor retarder (perm 6) housewrap
  • seams taped, top and bottom sealed (air barrier)
  • mesh wrap maintains drainage gap behind siding
  • water managed pre-formed corner trim for siding
  • Window flashings – to drain leaks to outside
  • Flexible, formable adhesive sill flashing membrane
  • fast, easy installation; durable adhesive
  • seamless sill corner protection
  • Flashing tapes – sequence, corner patches important

Foundations, 3 ways to elevate:

  • Each are 3 ft. above base flood elevation (BFE) for lowest flood insurance premiums & cushion of safety
  • Front – Slab cap on compacted fill inside stemwall
  • rebar reinforced concrete block (CMU) stemwalls on poured concrete footings
  • Resists pressure of floodwater
  • No crawl space, yet low impact on floodplain
  • Most expensive option
  • Durable plastic sheeting moisture barrier under slab + waterproofing between CMU & slab – stops wicking
  • Low water-cement ratio (<.47), wet curing blanket – for higher strength & reduced curl
  • recycled fly ash, slag, cement mix – adds strength
  • MBa – wood subfloor on stemwall foundation (crawl space)
  • CMU stem walls with flood vents (within 1 ft. of grade) to prevent damage from floodwater pressure
  • flood activated vents exhibited – louvered & insulated
  • Crawlspace ground higher than surrounding grade
  • Spray foam insulation (air barrier) + plastic ground cover
  • 2 types – open & closed cell being moisture monitored (research)
  • MBR – wood subfloor on piers and beams (open)
  • lowest cost option
  • spray foam perimeter rim (air seal) + foil faced rigid foam board insulation encasing joists, taped seams
  • Steel mesh termite barrier blocks hidden pathways
  • pipe collars, tops of piers and stemwalls

Energy saving features of west wing:

Passive solar (sun control)

  • Radiant barrier roof decking (2nd story), cool color metal roof
  • Foil faced sheathing behind west brick veneer (radiant barrier)
  • Little west glass, Bahamas shutters
  • Energy Star Low-e windows, doors (SHGC < 0.4)
  • Tight construction
  • exterior air barriers (stucco, taped sheathing, sealed wrap)
  • foam sealed penetrations
  • thin sheathing behind tubs, sealed to drywall
  • Airtight Drywall Approach in MBR (sealed drywall)
  • airtight attic access stair

Continuous insulation

  • R-19 spray cellulose in 2x6 walls
  • R-38 blown fiberglass over ceiling, with vent baffles

Efficient HVAC system

  • SEER 16, dual fuel air source heat pump
  • 90% AFUE gas back up heat (good for north La.)
  • Fresh air duct & smart flow controller for good IAQ
  • Ducts in conditioned space
  • dropped ceiling below sealed insulated ceiling,
  • between floors through open web joists
  • Air transfer grilles with light, sound baffles prevent pressure imbalances – protects air quality, saves energy, comfort

Efficient lighting & appliances

  • High color fluorescent fixtures

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

  • 15/32 in. structural wall sheathing for shear (racking) resistance
  • all exterior walls + load bearing interior walls that are subject to wind forces
  • placed to span, thus tie 1st to 2nd level
  • blocking added to provide framing at all edges
  • 10d nails spaced 6 in. along long edges, double row along short edges, 12 in. across field of each panel
  • Hurricane connectors tie roof to foundation:
  • 5/8 in. anchor bolts with 3 in. washers, 16 in. spacing, tie sole plate to slab
  • corner hold-downs resist sliding, tilting forces
  • Hurricane straps tie wood subfloors to piers, stemwall
  • Stud to plate connectors tie walls to foundation
  • Straps connect 2nd story to 1st story, studs to top plates
  • u-shaped rafter straps to top plates reinforce notched rafters, roof overhang from high uplift forces
  • porch columns strapped to piers and roof beam
  • 19/32 in. OSB roof decking
  • Ring shank nails (8d), spaced 6 in.
  • Peel and stick membrane roof underlayment
  • High performance tested – for adhesive tile installation
  • Primer applied to decking for optimal adhesn
  • 6:12 moderate slope hip roof – more wind resistant
  • wind borne debris protection:
  • impact rated windows, door (MBR)
  • impact rated shutters – varied types

Safe Room MBR closet:

  • Moderate level (not FEMA standard), low cost storm shelter
  • Separate safe room ceiling
  • 2 layers ¾ in. plywood sheathing
  • Hurricane connectors – slab to studs to ceiling joists
  • Hidden impact-resistant pocket door (+ cosmetic door) and swing impact door to water heater closet

MBR Deck

  • Copper azole treated for outdoor exposure (framing, rails)
  • Non-metallic pressured treated decking – eco-friendly
  • Deck protector tape protects hardware from corrosion

Roofs

  • Concrete tile (2nd story) installed with foam adhesive, large patty under each tile for high wind resistance
  • Roll ridge vent system with water barrier
  • More impact resistant, lower cost than clay
  • Long lasting roof
  • Standing seam metal roofing (MBR and MBa)
  • Long lasting, recycled content
  • Cool color pigment, solar reflective
  • No exposed fasteners, less leak prone

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