HOUSING                                           PIH-32


    Building Materials and Equipment for Swine Facilities

Vernon M. Meyer, Iowa State University
Gerald R. Bodman, University of Nebraska
William H. Friday, Purdue University

L. Neil Burcham, New Mexico State University
Robert M. Butler, University of Wisconsin
Nevin Wagner, Manheim, Pennsylvania

     Producers who have invested  in  new  swine  facilities  are
often  disappointed  by the severe deterioration of their facili-
ties after just a few years. Much of the deterioration could have
been  prevented  if the producer had considered the corrosiveness
of the environment within the facility and the pigs'  destructive
nature. These problems are more pronounced in enclosed facilities
but can occur in all types of units. The most rapid deterioration
takes  place  near  the floor because of wetness, chemical corro-
sion, and physical destruction.  However, the effects can also be
observed  in  other  parts  of the building, especially on unpro-
tected metal. Rapid  corrosion  of  metal  is  characteristic  of
facilities  with  a  poorly designed ventilation system. See Pork
Industry Handbook fact sheet PIH-60,  Mechanical  Ventilation  of
Swine Buildings.

     When planning  your  building,  select  materials  that  are
insurable,  corrosion-resistant,  and durable enough to withstand
the rugged pushing, rubbing and chewing activities of  the  pigs.
Materials  within  the  building  but outside the pens are not as
vulnerable to physical deterioration, but they can have  a  rela-
tively  short  life  because of corrosion. Materials along alleys
will be subjected to physical abuse from the pigs and from moving
equipment.   Therefore,  carefully select equipment and materials
regardless of their intended use or location.


     A good,  high-quality  concrete  mix  is  necessary  because
manure acids corrode concrete. Solid floors should be made from a
mix that will yield a 4,000 psi concrete (maximum of  6  gal.  of
water  per  bag of cement). Air entrained concrete should be used
for all installations, especially where the concrete will be sub-
jected  to  freezing  temperatures.  An alternative is to place a
lower strength, less expensive concrete as a base and then add  a
higher  strength concrete over the top as a wear surface. This is
accomplished by placing a steel reinforcement mesh over a  rough-
graded  layer  of concrete and then adding a finish layer of con-
crete. The savings in material cost should be evaluated in  light
of  possible inconvenience during the placement of layers of con-
crete and higher labor costs.

     If slats are to be used, they should be designed for  corro-
sion  resistance as well as strength.  Additional flooring design
details can be found in PIH-53, Flooring for Swine.


     Concrete and wood-frame are both satisfactory  for  exterior
walls.  A  choice should be made after considering both construc-
tion and maintenance costs. Consider also the  work  required  to
provide openings in the wall, such as for ventilation.

     Concrete is one of the most durable materials for walls that
are  subjected to animal and equipment contact. However, concrete
has little thermal insulating value. Where warm interior tempera-
tures  are to be maintained, as for a farrowing or nursery facil-
ity, additional insulation  is  recommended.  In  cold  climates,
insulation  is  also  essential in growing/finishing buildings to
prevent condensation and retain animal heat. In  very  mild  cli-
mates,  concrete  walls  without  insulation are satisfactory for
some phases of a hog production facility.

     Sandwich panel construction is an effective means of provid-
ing a durable interior and exterior surface and at the same time,
improving the thermal efficiency of the wall. Sandwich panels are
formed  by  placing  a  foam board insulation material within the
wall during casting of the concrete. This can be done either with
cast-in-place walls or precast, tilt-up panels.

     An alternative that can be used where animals  do  not  have
access to the outside of the building is to erect a concrete wall
and apply a spray-on urethane insulation material on the outside.
The  insulation  must be painted or otherwise protected to retard
destruction by ultraviolet light from the sun.  For added protec-
tion, the foam should be covered with a 1/4-in. layer of spray-on
plaster or gunite concrete. The result is  a  durable,  thermally
efficient, stucco-like wall.

     Wood-frame walls may be of conventional stud frame  or  post
frame  construction. In either case a wider range of materials is
available for enclosing the exterior frame. Among  the  materials
that  have  been  used successfully are ribbed steel or aluminum;
composition boards, such as particle board or hardboard; exterior
plywood;  and boards. As with all wall construction, both initial
and maintenance costs, as well as useful  life,  should  be  con-
sidered before deciding on the material to use.

     With either type of wall, stud or post,  thermal  insulation
can be added easily. However, appropriate construction plans must
be followed, such as planning stud or girt spacings  to  accommo-
date  standard widths of insulation materials. The range of insu-
lation materials is broad and includes fiberglass blankets,  pour
insulation,  foam  boards  and  spray-on foams. Regardless of the
insulation material chosen, an interior  protective  covering  is

     Where walls are exposed only to personnel and  will  not  be
subjected  to  hog  contact  or  vehicular traffic, the choice of
interior covering materials would include the same  materials  as
for exterior surfaces.

     The potential for both vehicular traffic and animal  contact
makes  the  use of the more durable interior coverings desirable.
For occasional contact, such as along alleys used for  hog  move-
ment,  ribbed  sheet metals, plywood, wood boards and composition
boards are good choices. For continual contact, as in  pens,  the
use  of  solid  coverings   hardwood,  steel sheets or panels, or
fiberglass-reinforced plastics  (FRP)   is  recommended.  Plastic
mouldings  used with FRP panels should be located at the pen par-
titions or fastened very securely so as not to give  the  pigs  a
place  to  start  chewing.  The FRP material is also available in
roll form in long lengths thereby reducing the number of possible

     On wall areas above the reach of the animals  (usually  con-
sidered to be about 4 ft.), most common building materials can be
used. However, since sanitation is important in swine  buildings,
these  lining materials should be nonporous and durable enough to
withstand cleaning with a high-pressure water system.


     The main requirements for a ceiling material are cleanabili-
ty  and  corrosion  resistance.  Like wall sections above the hog
contact areas, most common building materials can be used.

     Since roof trusses are usually spaced 4 ft. on  center,  the
cost  of  any  additional  nailers required for installation of a
particular ceiling product should also be considered as  part  of
the  ceiling cost. Materials such as ribbed metal can be attached
directly to truss chords without additional nailers.

Insulation and Vapor Barriers

     Where insulation is to be used, consider the purchase price,
installation cost, required coverings, and thermal effectiveness.
In measuring thermal effectiveness, it is recommended that  insu-
lation  or ``R'' values as given by the American Society of Heat-
ing, Refrigerating, and Air-Conditioning  Engineers  (ASHRAE)  be
used (Table 1).

     The high moisture levels in swine  facilities  require  that
appropriate  vapor  barriers  be used. These are needed to reduce
the movement of water vapor into  a  wall  or  ceiling.  Allowing
water  vapor  to  move into a wall will cause condensation within
the wall or ceiling assembly. The condensation will result  in  a
lower   R-value   and  possible  destruction  of  the  insulation
material. In general, a 4-6 mil plastic (polyethylene) vapor bar-
rier  should  be used with all insulation materials because, even
with vinyl-clad foam boards, it is  impossible  to  maintain  all
joints  in  a water vapor-tight condition. In all cases the vapor
barrier should be located on the warm side (inside) of  the  wall
or  ceiling between the interior covering and the insulation. See
PIH-65, Insulation for Swine Housing.

     Figure 1 illustrates the procedures of  determining  the  R-
value for a concrete block wall using the data in Table 1. Figure
2 shows how to calculate the R value of a ceiling. Figure 3 shows
winter  degree  days,  and  Table 2 recommends minimum insulation
levels for swine buildings.

     Mice, other rodents, and birds can seriously damage any type
of  insulation.  See  PIH-107, Controlling Rats and Mice in Swine
Facilities. Use physical barriers to keep rodents out  of  build-
ings.  If  ribbed  metal is used for inside wall linings, the end
openings of the ribs should be closed to prevent the entrance  of
rodents.  A  good  rodent control program is essential since they

Table 2. Recommended minimum insulation levels for  swine  build-
ings. R values are for building sections.

                         Recommended minimum R values
                                   Modified      Supplementally
Winter            ``Cold''       environment         heated
  degree days  Walls  Ceiling   Walls  Ceiling  Walls   Ceiling
2500 or less             6        6      14       14       22
2501 to 6000             6        6      17       14       25
6001 or more             6       12      25       20       33

Birds will destroy any exposed insulation. In some cases  insula-
tion  is  consumed  directly  as food, while in other cases it is
used as a nesting location, a material for nest building, or sim-
ply  something to play with to pass the time. Consequently, cover
the insulation and use an effective bird control program.

Pen Partitions

     Pen partitions must be durable  enough  to  resist  rubbing,
chewing  and  pushing  by  pigs and, at the same time, resist the
corrosion of the environment and manure that comes  into  contact
with  them.  The choice of materials depends partially on whether
open or solid partitions are used and whether  the  partition  is
permanent  or must be movable. Partitions are generally not insu-

     The durability and general corrosion resistance of  concrete
makes it an excellent choice for partitions (minimum of 3500 psi;
7 gal. water per bag of cement is recommended). Concrete  blocks,
cast-in-place  concrete,  or  precast concrete panels can be used
(Figure 4). As with exterior walls,  steel  reinforcing  bars  or
mesh  should  be  a  part  of  all  concrete partitions to afford
greater strength and to fasten partitions securely to the  floor.
When  anchoring  equipment  to  floors  or  walls, consider using
stainless steel materials.

     Woods such as oak and southern yellow pine are  fairly  dur-
able  when used as pen partitions. A key requirement with wood is
to restrict pigs from chewing it. Use  tongue-and-grooved  planks
or  well-matched  planks  to reduce access to edges where chewing
can start. Softwoods will probably have a useful life of 2  years
or  less.  Hence,  their  use  should  be restricted to temporary
shelters. As with exterior walls, the life of partitions  can  be
extended by overlaying the basic wood partition with such materi-
als as fiberglass-reinforced plastics,  steel  sheets,  or  mesh.
Where  wood is in contact with the floor, ground or generally wet
conditions, the use of pressure  preservative-treated  lumber  is
recommended for a longer use life.

     Both solid steel sheets and open welded wire mesh have  been
used  for pen partitions with poor results. The most common steel
panels use vertical rods or tubing. The life of  these  materials
depends  upon  how  well  they  can  resist corrosion and flexing
because of pushing by the pigs. To maintain partitions and reduce
injury  to pigs, all joints must be securely welded and protected
from corrosion. Plain steel panels can be  satisfactory  if  well
protected  with  a  long-lasting  coating. The abrasive action of
hogs wears away most post-installation coatings such as paint  or
epoxy.  Also,  once  corrosion starts, it tends to work under the
remaining coating and lift  it  away.  Stainless  steel  is  more
expensive  but  might  be  worth the additional cost in permanent
structures subjected to intensive use.

     Fiberglass panels with vertical bars are now  available  and
appear  durable. Solid plastic planks are available for use where
a solid partition is desired or needed.

Farrowing Stalls

     Material used for farrowing stalls includes stainless steel,
aluminum,  fiberglass, or galvanized and painted metal. Any metal
near the stall floor is subject to extreme corrosion while  parts
of  the  stall's upper metal is subject to wear from the abrasion
of sows rubbing. Aluminum stalls  require  nonmetalic  insulating
spacers  to  prevent  contact with concrete or dissimilar metals,
and galvanic corrosion.

     As with pen partitions, rusting will start quickly at unpro-
tected  spots  on the steel stalls. A heavy galvanized coat helps
but galvanizing will wear and corrode off in time.

     A quality steel farrowing stall will have all welds  cleaned
thoroughly,  a good prime coat applied and a tough, durable, fin-
ish paint coat applied over it.

     The life of all metal equipment will be extended  with  good
ventilation  to keep air in the hog house drier and lower in cor-
rosive gases and by periodic cleaning and painting at  the  floor

Plastic Pans

     When remodeling a farrowing or nursery unit, it is sometimes
more practical to use the existing floor as is, and install plas-
tic pans or trays under the slotted floor to contain the  manure.
Manure  may  be drained into a pipe that collects from each crate
or deck and carries the manure to storage.  In some cases a plas-
tic auger can be used to convey the manure to the end of a row of
crates or decks and then drain into storage. Some producers  have
indicated that at times, manure sticks to the plastic and must be
cleaned with a high pressure cleaning system at cleanup time.  An
alternative  is  to  partially fill the pan with water after each
drain. This improves cleaning ability but  requires  handling  of
greater   amounts  of  liquid  manure.  Plastic  pans  should  be
installed so that access is provided for hand scraping and  pres-
sure washing without having to spray through the floor.

Roof Coverings

     The most common covering  materials  are  plain  or  painted
ribbed  aluminum, galvanized or painted steel sheets, and asphalt
shingles. All of these are satisfactory if good quality materials
are purchased and properly applied.

     With galvanized steel, the use  of  sheets  bearing  a  Zinc
Institute,  Inc.   grade  stamp  is recommended. Outdoor exposure
studies at The Pennsylvania State University revealed that sheets
with  a  2-oz. zinc coating and a ``Seal of Quality'' grade stamp
required 15 years of exposure before the  first  signs  of  rust.
Sheets  with a 11/4-oz. zinc coating began to rust after 7 years.
Sheets with less zinc per square foot than these  industry  stan-
dards are available at lower cost and will have a correspondingly
shorter life before the first signs of rust. It is  not  possible
to  determine  the  amount  of zinc coating by visual inspection.
Even where factory applied finishes are used,  the  heavier  zinc
coatings should be used.

     Galvanized and painted steel is sold on the basis of  thick-
ness or gage.  Gages most commonly available are 28 and 29. Lower
gage numbers indicate greater thickness. A choice should  include
consideration  of  required roof design loads in the area and the
load-carrying capacity of  the  roofing  sheets.   Manufacturers'
literature and local codes can provide the required information.

     In selecting aluminum roofing sheets the ease  of  installa-
tion  should be considered. The use of high-strength alloy sheets
of less thickness might be a  disadvantage  since  their  greater
brittleness  tends to cause them to split rather than dent if hit
too hard or stepped on improperly. Avoid  the  use  of  extremely
long  sheets because of changes in length with variations in tem-
perature. This results in tearing out of nail holes,  or  bending
or  extraction  of  nails  or other fasteners. Fewer roof-leakage
problems are generally experienced where the  length  of  roofing
sheets is kept to 24 ft. or less.

     To prevent  corrosion  of  metal  roofing  through  galvanic
action,  it is imperative that the correct fasteners be used with
each kind of metal.  Also, galvanized and aluminum sheets  should
not  be  placed in contact with each other. Where it is necessary
to mix galvanized and aluminum products, they should be separated
by a nonmetallic intermediate material.

     When installing asphalt shingles, use at least 235-lb. shin-
gles with self-sealing tabs.

     Regardless of the roofing material used, the limitations  of
its use as related to roof slope should be recognized.


     PVC or similar plastic pipe is probably  the  most  suitable
for a swine building environment. Because of the corrosive atmos-
phere within swine facilities, metal pipe  should  be  used  with
caution.  Copper  pipe usually has a short life when exposed in a
swine building. If galvanized or black iron pipe  is  used,  some
type  of coating should be applied at the threads since this part
of the pipe is most subject to deterioration and failure.

     In warm facilities, plumbing can be run overhead  to  reduce
contact  with  animals and manure. Although overhead pipes can be
used in cold buildings, such placement requires  electrical  heat
tape  and  pipe  insulation to prevent freezing. Consequently, in
cold facilities underground plumbing is recommended. Where  pipes
are  brought  to  the  surface,  they can be run through a large-
diameter plastic pipe to  reduce  corrosion  and  provide  easier

     In cold facilities, built-in  heating  units  are  suggested
where  cup waterers are used. Nipple waterers (Table 3) generally
do not require additional freeze protection beyond that  provided
on  the  pipe  up  to  the nipple.  In all cases, a durable high-
strength cover is required over pipe insulation and heat tape  to
reduce  damage  by pigs and reduce the potential of electrocution
of pigs. Adequate grounding of  all  electrical  equipment  is  a
MUST.  Good-quality waterers should be selected to reduce mainte-
nance costs, extend the use life  of  the  waterers,  and  reduce
water  usage  and  manure  hauling  costs  resulting from leaking

Table 3. Planning guide, nipple waterers.*

                      Pig weight, lb.        and
Item           <  12 12-3030-7575-100100-240boar
Height, in.     4-6  6-12 12-1818-24  24-30 30-36
Pigs/nipple    litter 10   10  12-15  12-15 12-15
Min. flow
  rates, quarts
   per min.     0.2   0.2  0.4  0.5   0.67   1.0

* Install at least two waterers per  pen.   Locate waterers 14"
apart for nursery pigs; 24" for larger  pigs. This distance may
be reduced some if the  nipples are   angled   away  from  each


     This may be the most critical component of a swine  building
since  corrosion  can create conditions that increase the risk of
fire and electrical shock. Electrical materials installed  inside
a  swine  building  should be designed for damp or wet locations.
Thin-wall metal conduit has a short life and should not be  used.
Fittings,  outlet  boxes and switches not designed for waterproof
locations may create an unsafe condition after several years.  If
conduit  is used, it should be plastic. Type UF cable with water-
proof fittings is another option. If at all possible, locate  the
entrance  box  in  a  dry annex of the office room to avoid rapid
corrosion. Only surface-mount boxes should be used, especially on
outside  walls.  See  PIH-110, Electrical Wiring for Swine Build-
ings. In cold climates, problems can be reduced if all conduit is
installed  within  the  warm  part  of the building. When conduit
extends from the warm building up into the cold  loft  or  attic,
condensation  can  occur and the resulting moisture can move back
to a fitting and cause corrosion or electrical faults. If a posi-
tive  pressure ventilation system is used, be sure that no moist,
corrosive air can be pushed into electrical boxes.

     As noted in the discussion on  plumbing,  grounding  of  all
electrical  equipment  is  a  MUST. This applies to all switches,
receptacles and appliances since wet  floors  increase  the  con-
tinual threat of shock and possible electrocution of both person-
nel and animals. All electrical equipment and  wiring  should  be
installed in accordance with the National Electrical Code.  Check
with your electrician or power supplier.


     A low-quality feeder (Table 4) will not last long in  a  hog
house. The increased moisture level near the floor speeds up cor-
rosion. The activity of the pigs causes  rapid  wear.  The  upper
part  of  the  feeder may last more than 10 years, but this helps
little if the bottom has failed.

     When purchasing a metal feeder, look for stainless steel  or
cast  iron  bottoms. Wood feeders can be improved by covering the
wooden trough with a more durable material such as fiberglass  or
metal.  Plastic feeders resist corrosion and appear durable.

     As with plumbing and electrical lines, the running  of  feed
conveyance  equipment  through  a  ceiling should be minimized to
reduce the risk of moisture condensation and the loss of heat.

     Ease of adjustment in a feeder is as important  as  durabil-
ity. If a feeder cannot be easily adjusted to prevent feed waste,
it can easily cost its owner many times  its  replacement  value.
Feeders  with  flat  bottoms reduce shelter areas for rodents and
are recommended.

Table 4. Feeder space.
Pig weight, lb.                                 Pigs/feeder space
12-15                                                   2
25-50                                                   3
50-120                                                  4
120-240                                                4-5


Reference to products in this publication is not intended  to  be
an  endorsement to the exclusion of others that might be similar.
Persons using such products assume responsibility for  their  use
in accordance with current label directions of the manufacturer.

REV 12/88 (5M)


Cooperative Extension Work in  Agriculture  and  Home  Economics,
State  of Indiana, Purdue University and U.S. Department of Agri-
culture Cooperating. H.A. Wadsworth,  Director,  West  Lafayette,
IN. Issued in furtherance of the Acts of May 8 and June 30, 1914.
It is the policy of the Cooperative Extension Service  of  Purdue
University  that  all  persons  shall  have equal opportunity and
             access to our programs and facilities.