X.D. Construction Specifications

The following summary of specifications is by no means complete, but gives an overview of the specific requirements identified by the Board of Directors as being necessary in all GHI additions and improvements.


  1. Placement. Careful thought should be given to the architectural design of any addition. The structure will be present for many years and members are urged to have that fact in mind when preparing plans. The plans should provide for a structurally sound and attractive addition. Any exterior addition should maintain the architectural style of the building.

  2. Foundations. In all additions, continuous concrete footings must be placed in accordance with Prince George's County building code regulations; wood pilings or cinder blocks set on the ground are not permitted. If the addition is to have a wood floor, it must be insulated against heat loss and the ground must be covered with polyethylene vapor barrier to guard against dampness. For crawlspaces designed as vented, foundation walls must include vents to prevent vapor accumulation. For crawlspaces designed as unvented (preferred) no exterior vents are required. Access is necessary to the crawl space beneath the addition floor and an access panel must be placed in the foundation wall, in the floor of the addition, or from the crawl space of the main building.

  3. Termite Treatment. The entire foundation area and other disturbed areas shall be treated for subterranean termites by an approved contractor. The use of chlordane is prohibited. Proof of termite treatment is required before final approval may be given by GHI. Any wood within twelve inches of the ground shall be pressure treated with a minimum of forty percent concentration. For new unvented addition construction, a termite shield shall extend from below the sill plate to the interior to cover the rigid foam insulation extending down 2 inches.

  4. Insulation. The building envelope of enclosures and additions shall be insulated in accordance with the building code applicable at the time of construction or modification.

A. For improvement of existing open masonry porches with concrete floors    
           and foundations:

      i.     If not heated, maintain insulation across porch opening, at      
             original building foundation wall.

                              ii.     If heated, insulate all walls of porch bump-out except for walls    

                                     that adjoin another conditioned crawlspace.

                                         iii.     Install minimum 10 mil ground vapor barrier to extend up the
                                                 wall a minimum 12 inches; tape all seams and seal to the wall
                                                 surface.

          B. New addition crawlspaces should be partially conditioned, and not vented  
                       to the exterior.

                              i.     Foundation walls:  insulated R-10, using 2” XPS or 2"
                                     polyisocyanurate board attached mechanically to the   
                                     foundation walls with seams taped.

                              ii.     No foundation vents to the exterior.

                             iii.     Install perimeter drainage per plans as required per site
                                     conditions.

                             iv.     Install a full ground vapor barrier, minimum 10 mil; tape all   
                                     seams and attach to all vertical surfaces a minimum of 12 inches
                                     and seal to the wall surface.

C. Insulation materials

                                           i.     Material shall be a minimum R-10, 2” nominal extruded
                                                 polystyrene (XPS) rigid foam board. Insulation materials shall
                                                 have specific approval for use without an ignition barrier in an
                                                 unvented crawl space or be covered with an approved ignition
                                                 barrier material.

                                          ii.     All tapes, sealants, and adhesives in contact with insulation shall  

                                                 be listed by manufacturer as compatible with the insulation (for

                                                 effective adherence and sealing, and without causing    

                                                 deterioration).

                                         iii.     Joints shall be sealed using tape, or approved equal by same
                                                 manufacturer as for foam board insulation.

                                         iv.     Shall be permanently attached to the foundation wall using  
                                                 mechanical fasteners.

D. Air Seal & firestop

                                           i.      Penetrations through the floor (at electrical wiring,
                                                  communications wiring, plumbing, and other openings) shall be
                                                  sealed from the crawl space using fire rated caulk or foam and
                                                  backing material or rod as required for large cracks or openings
                                                  in accordance with manufacturer’s installations instructions.

                                          ii.      Penetrations in the foundation wall shall be sealed from the
                                                  crawl space using the sealant specified for the floor penetrations
                                                  or rim areas.  Also, air seal the closed foundation vents.

                                         iii.      It is not necessary to remove existing sealant at penetrations if   
                                                  that sealant is complete and appears to be providing an effective
                                                  air seal.

5. Heating. All enclosed additions intended as habitable living space, including bathrooms, shall have adequate heating. Specific permission must be received by management to install a fireplace with a chimney either in the original structure or in a proposed addition. See section XXI, FIREPLACES AND WOOD STOVES for further information.

6. Plumbing. Plumbing installations in additions shall be done by licensed plumbers and detailed drawings for all plumbing work must be included in the working drawing submitted to the Technical Services Office. The installation of washing machines, dishwashers, new sinks, and other fixtures shall be done according to W.S.S.C. code requirements. Check valves on both hot and cold water lines are required for washing machines. Connections made necessary by an addition, enclosure or any outside faucet to the hot or cold water systems of the main building must be made in such manner as designated by the corporation. No supply tap-in shall be made directly to the main line in the crawl space with the exception of outside faucets. Other lines must be connected after

the first valve in the main unit. Drawings of typical tie-ins are available in the Technical Services Office. All waste lines must be properly vented. Under certain circumstances, loop vents for certain fixtures or appliances will be allowed. Schematic diagrams must indicate where in the building these vents will be located and where roof penetrations will be made.

7. Electrical. Electrical installations in additions shall be done by licensed electricians, and detailed drawings for all electric work must be included in the working drawings submitted to the Technical Services Office. All electrical connections shall be made at the main distribution breaker panel or at a new sub-panel. Catalog data on all new panel equipment plus any appliances must be submitted for approval. All electrical work done at GHI will require a County permit. For significant changes impacting a home's electric requirements (e.g. substantial addition of area, HVAC, appliances with electric resistance heating), electrical calculations justifying the proposed configuration load to the electric service (compliant with industry standards such as NEC article 220) are required, signed by a licensed Master Electrician, including license number and date.

8. Structural. Floor joists, walls, ceiling joists, and roof rafters will be sized and spaced to maintain structural integrity and to avoid excessive deflection. Floor and roof sheathing for additions must be at least one-half inch thick plywood. Ceiling joists must be designed for the intended attic loads. If extra heavy loads, such as books, are intended to be stored in the attic then the proper reinforcement is necessary. All open spans including doorways and window openings shall have adequate headers. Loads must also be capable of being safely distributed down to the foundation. All structural members must be specified in the plans. Prefabricated, 3-season additions having components made of specialty, non-standard materials, such as vinyl-covered aluminum extrusions or uncovered insulated roof panels, are not allowed. Walls that extend to the lot line of the adjacent unit must have, as part of the construction, fire resistant materials in accordance with County code.

9. Gutters and downspouts. Additions to GHI homes shall not obstruct the flow of water via gutters and downspouts from the main roof. When constructing additions, this list of installation guidelines for modifying existing gutter and downspout locations shall be followed.

  1. If an addition is constructed in an area where there is currently a storm drain, this storm drain must be extended/relocated to the outside edge of the addition in order to pick up the downspout.

  2. If the downspout from the main structure is near the edge of the addition, it must continue along the roof of the addition and elbow into the same size document attached to the addition gutter. The gutter can be five (5) inch K-type since it is only carrying the water from the addition and not the main roof.

  3. If a downspout is located in the middle of a roof, the water can exit the downspout and flow across the roof to be picked up by the gutter on the addition provided the following conditions are met:

    1. There shall be a piece of flashing under the downspout to prevent shingle erosion.

    2. The gutter on the addition shall be of the same size as the gutter on the main structure (6-inch K-type gutter) and the gutter must have a 3-inch by 4-inch downspout of the same gauge as the main structure exiting to positive drainage

  4. Should it be necessary to relocate downspouts, etc., to accommodate the erection of the addition, the move must be made at the member's expense and conform to the requirements of the corporation.

10. Ventilation. All spaces above the finished ceiling must be properly ventilated. This ventilation must allow for air flow above the ceiling insulation. This may be accomplished in all cases by the use of such ventilation devices as soffit vents, gable vents, and ridge vents. When cathedral ceilings are constructed, sufficient air space shall be furnished above the insulation. Ventilation may be accomplished by a continuous soffit vent and a continuous flashing vent on shed roofs or ridge vent on gable roofs. Contact the Technical Services Office for further information. All plans for mechanical ventilation of crawl spaces, attic spaces or of interior spaces must be specified in the submittal drawings.

11. Grading and Drainage. Normal improvements in grounds within a member's yard do not   
           require the permission of the corporation. Normal improvements include flower planting     
           and gardening, providing yard swales or grade level is not disturbed in any manner.
           Written approval must be obtained from the Technical Services Office before any
           alteration to a yard swale or change in grade level in any yard can be made by a GHI
           member. Changes in the yard swale may require the installation of drain tile.

Careful consideration must be given to drainage patterns in a member' yard when making
           improvements or planting hedges. Placement of soil to build up a yard level often creates
           poor drainage conditions. Placement of an addition in a yard swale is not
           permitted. 

When making improvements, members and their contractors shall seek to
           protect trees, shrubs, and other landscape plantings in yards and common areas from
           damage. Members shall consult GHI staff prior to site construction to determine if any
           mature trees may be adversely impacted by proposed construction. Members are required
           to minimize damage to trees over eight (8) feet and their associated root areas.
           Construction traffic and material storage shall be kept away from tree root areas as
           specified by GHI staff.

Required protective measures for trees might include temporary
           fencing around trees, use of temporary protective sheeting to reduce soil compaction in
           root zone areas, and the storing of building supplies away from trees and root areas.
           Parking lots and sidewalks shall be cleaned of dirt and debris by the end of each day.
           Building materials shall be stored or stacked in an orderly fashion during construction
           and construction debris shall be contained in canisters or dumpsters. GHI staff shall
           instruct members on the placement of canisters or dumpsters.

Excess and waste materials shall be promptly and properly removed in accordance with local laws. Debris and soil shall not be disposed of in common areas or on City property. Members shall take steps to prevent erosion during the construction phase. Exposed soil must be temporarily or  permanently stabilized within seven (7) days on all yard perimeters and slopes greater than three (3) horizontal to one (1) vertical (3:1); and fourteen (14) days for all other areas. Final grading must establish a positive grade away from the foundation of the building as applicable to the particular site.

When common areas must be crossed to perform work, every effort should be made to prevent damage. If damage should occur, members shall ensure their yard and common areas are restored to their original condition, or better, by the member and/or their contractor. Any damage to the grade (ruts, tracks, etc.) shall be repaired. Any damage caused to trees, shrubs, or other landscape plants in common areas and any damage to tree over eight (8) feet in a yard shall be repaired or replaced as specified by GHI staff. Any damage to sidewalks should be reported to GHI staff immediately. GHI staff will advise members of necessary action for reparation.


12. Exterior Walls

  1. Exterior walls of GHI additions must conform to the following materials:

addns to

Acceptable on Additions

Unacceptable

frame homes

- vinyl siding

horizontal lap only

4 or 8 inch exposure

white or color to match existing

- fiber-cement siding

horizontal lap only

4 or 8 inch exposure

white or color to match existing

vertical siding 
aluminum siding 
steel siding 
shingles / shakes 
plywood (T-111)

brick homes

- brick - match size

white or color to match existing


- vinyl siding

horizontal lap only

4 or 8 inch exposure

white or color to match existing

      - fiber-cement siding

horizontal lap only

4 or 8 inch exposure

white or color to match existing

vertical siding 
aluminum siding 
steel siding 
plywood (T-111) 
concrete block


lock homes

- block - match size

white or color to match existing


- vinyl siding

horizontal lap only

4 or 8 inch exposure

white or color to match existing


- fiber-cement siding

horizontal lap only

4 or 8 inch exposure

white or color to match existing

vertical siding 
aluminum siding 
steel siding 
plywood (T-111)


2. Any other exterior wall materials shall be only as acceptable to GHI staff and approved by the GHI Board of Directors.

3. Installation of vinyl siding to cover the original walls of block homes must be approved by the Board of Directors.

4. Specialty, non-standard material such as vinyl-covered extruded aluminum, insulated roof panels, etc. (ref. X.D.8.), are not acceptable.

5. Shutters are not considered to be trim. For the Homes Improvement Program (HIP), shutters shall conform only to the door color palette selected for HIP doors, and are not allowed to be painted any color (with neighbor approval) as doors are.

6. Exterior trim shall be materials not requiring regular maintenance (i.e. painting), such as vinyl-coated aluminum over wood trim.


13. Based on roof pitch, acceptable roofing materials for additions are as follows:


                                                                                                                               Original home

Roof pitch

Material

Brick

Block

frame

>=3:12

architectural shingles, CertainTeed Landmark, Pewterwood color, or equivalent

Ok

Ok

Ok


slate

Ok

No

No

<3:12

asphalt sheet (modified bitumen only)

Ok

Ok

Ok

<=1:12

EPDM (ethylene propylene diene monomer)

Ok

Ok

Ok


any corrugated roof panels

No

No

No

 

Any other roofing materials shall be only as acceptable to GHI staff and approved by the GHI Board of Directors.