Construction FAQ

Need to know how Ferrocement building works? How-to FAQs related to: am-cor Prefab Kit Assembly & Construction

What type of foundation do I need?

Gen­er­ally, you need a stand­ard strip foot­ing, with some sim­pli­fic­a­tions.

The stand­ard pro­ced­ure for am-cor Found­a­tions is:

  • Re­view Struc­tur­al Set (i.e.: am-cor en­gin­eer­ing draw­ings) provided with your am-cor Kit.
  • Place am-cor foot­ing trays in the found­a­tion trench as pre­fab­ric­ated foot­ing form­work for the con­crete
  • Place am-cor ex­ter­i­or wall pan­els in the foot­ing trays, brace and plumb the wall pan­els
  • Fasten am-cor wall pan­els to the foot­ing trays and to each oth­er
  • Depth of foot­ing be­low fin­ish grade de­pends on site loc­a­tion; your am-cor Kit's wall pan­els will be de­signed & struc­tured based on build­ing code for your re­gion.
  • These am-cor wall pan­els act as the slab, foot­ing & stem wall form­work when you pour the floor slab; the wall pan­els are then em­bed­ded & in­teg­rated in­to the found­a­tion, not just pinned to the slab sur­face.
NB: The am-cor Sys­tem sim­pli­fies con­struc­tion, as you only need to provide a level trench bot­tom to start shell & floor con­struc­tion.

For de­tails, see the Found­a­tion phase in our Comparisons sec­tion.

What kind of interior finishes are available?

Cus­tom­ers have fin­ished the in­teri­ors of their am-cor Kits with:

  • gypsum dry­wall/sheet­rock (cheapest, most pre­val­ent)
  • in­teri­or wood pan­el­ing
  • in­teri­or plaster/stucco (more labor in­tens­ive, most dur­able & pro­fes­sion­al)
  • ce­ment board (sim­il­ar to dry­wall, but stiffer, stronger, more mois­ture res­ist­ant, more ex­pens­ive)
  • tile (marble, ceram­ic, etc.)
  • in­teri­or lam­in­ate/polycar­bon­ate pan­el­ing/boards (usu­ally used in com­mer­cial/re­tail, some­times res­id­en­tial)
These sur­faces are ap­plied in the same man­ner as typ­ic­al light gauge steel framed con­struc­tion.
Ba­sic­ally, any stand­ard in­teri­or fin­ish product can be ap­plied to the in­teri­or frame of an am-cor Kit. Of­ten the dry­wall, ce­ment board, and plaster stucco sur­faces look the same from a dis­tance, but stucco & ce­ment board are more dur­able: they feel more sol­id and do not scratch or dent as eas­ily as dry­wall.

How do I weatherproof exterior surfaces?

Ba­sic­ally, the same as you would weather­proof any con­crete sur­face.
A num­ber of ma­ter­i­als can be used for weather­proof­ing am­cor­ite ex­ter­i­or wall and roof sur­faces. Vir­tu­ally any fin­ish ma­ter­i­al which is weather­proof, and is ap­plic­able for use on con­crete and ce­ment sur­faces will be ef­fect­ive. Be­ware plastic based fin­ishes sub­ject to de­teri­or­a­tion from Ul­tra Vi­ol­et (UV) sun­light ex­pos­ure, as they will even­tu­ally crack shrink and peel, leav­ing points of mois­ture pen­et­ra­tion. Com­pare ad­vert­ising claims with product war­ranty lim­it­a­tions. am­cor­ite is ex­tremely dur­able and you want an equally dur­able fin­ish coat.
Be­low grade, stand­ard con­crete va­por bar­ri­ers are used.

Is there any waste with am-cor Kits?

No.  There is no cut­ting re­quired with am-cor Kit as­sembly, and there­fore no struc­tur­al waste or cart­age re­quired on am-cor build­ing sites.

What kind of exterior finishes are available?

Cus­tom­ers have in­stalled the fol­low­ing ex­ter­i­or wall fin­ishes:

  • sid­ing (wood/vinyl/met­al),
  • stone/ma­sonry,
  • brick­work
  • stucco,
  • etc.
We re­com­mend weather­proof ac­ryl­ic stucco fin­ishes; there are a num­ber avail­able from dif­fer­ent sup­pli­ers. To the in­staller of the ex­ter­i­or fin­ish, the sub­strate of Fer­ro­cement struc­tur­al stucco acts, looks & feels just like a stand­ard, rough con­crete sur­face.

See our Galleries for ex­amples of dif­fer­ent ex­ter­i­or sur­faces on am-cor Kits.

Do I need to decide on my windows beforehand?

Yes. It is very im­port­ant that your win­dow and door units fit prop­erly dur­ing Kit as­sembly. We cus­tom­ize your Kit to suit your choice of win­dows and ex­ter­i­or doors, and it's ex­pens­ive to modi­fy your Kit after fab­ric­a­tion.

Are am-cor Panels the full building height?

Wall pan­el height de­pends on the build­ing type. Gen­er­ally, am-cor ex­ter­i­or wall pan­els are the height of each story:

  • Ground floor wall pan­els are fastened to the am-cor foot­ing trays and reach to the floor above. This provides struc­tur­al con­tinu­ity from foot­ing to second floor or roof
  • Up­per floor pan­els reach to each suc­cess­ive story, so that the pan­els re­main light and eas­ily handled and placed at each level.
Av­er­age wall pan­el height:
  • Res­id­en­tial/Com­mer­cial/Re­tail = 10' (3m) to 14' (4m)
  • In­dus­tri­al/Ware­house = 14' (4m) to 32' (10m)
If you have a spe­cial struc­tur­al/di­men­sion­al need, we can design for it. Contact us.

What's the maximum height of an am-cor building?

The am-cor Sys­tem can be built to any height reached by either stand­ard steel or re­in­forced con­crete con­struc­tion. Ba­sic­ally, we can go as high as any­body else.

An am-cor build­ing shell will be stronger and light­er than its stand­ard struc­tur­al coun­ter­part at any height. The am-cor Sys­tem is a life-sav­ing con­struc­tion meth­od, in­cor­por­at­ing both a mono­coque steel frame en­cased in and in­teg­rated with a seam­less struc­tur­al Ferrocement (highly re­in­forced thin ce­ment) skin. As such, it is a com­pos­ite & re­dund­ant struc­ture, highly res­ist­ant to lat­er­al forces such as wind, storm surge, and earth­quake. For in­stance, in a stand­ard high-rise steel or con­crete struc­ture, if sev­er­al ma­jor columns are re­moved, the build­ing will col­lapse. If sev­er­al of the columns in an am-cor high-rise struc­ture are re­moved, the unibody Fer­ro­cement stress-skin shell trans­fers the load to the re­main­ing mem­bers without col­lapsing.

Is the am-cor System strong enough?

Yes. The am-cor Sys­tem is def­in­itely as strong as, if not stronger than stand­ard con­struc­tion. To com­pare:

  • am-cor vs. wood con­struc­tion = Far stronger.
    • The am-cor Sys­tem's Fer­ro­cement struc­tur­al skin is or­ders of mag­nitude stronger than wood con­struc­tion.
    • Fer­ro­cement is made of steel, which flexes un­der ap­plied force, while wood splin­ters.
    • Wood com­pon­ents (studs, beams, rafters, poles, etc.) are usu­ally con­nec­ted with fasten­ers (nails, screws, bolts, etc.). Both these fasten­ers and their wood sub­strates fail over time, un­der re­peated ap­plied force.
    • As soon as a wood build­ing is com­pleted, its struc­ture be­comes pro­gress­ively weak­er, through:
      • age & mold/mil­dew/rot
      • mois­ture dam­age
      • con­sumed by ter­mites, ver­min, oth­er in­sects, bac­teria, an­im­als, etc.
      • ex­pan­sion & con­trac­tion of met­al fasten­ers
    • In com­par­is­on, ce­ment strengthens as it ages, and steel & ce­ment ex­pand & con­tract at the same rate.
  • am-cor vs. SIPs = Far stronger.
    • Struc­tur­al In­su­lated Pan­els are gen­er­ally made of a non-dur­able in­ner and out skin, sep­ar­ated by foam in­su­la­tion (e.g.: poly­styrene).
    • They are ac­tu­ally not sig­ni­fic­antly stronger than poly­styrene (not a rated struc­tur­al ma­ter­i­al).
    • Their strength is fur­ther lim­ited by the strength of the ad­hes­ive hold­ing the foam to the ex­ter­i­or pan­el faces.
    • Fa­cing ma­ter­i­al is of­ten made of chip­board or gypsum board (low struc­tur­ally rated ma­ter­i­als), which have many of the same is­sues noted above re: wood.
  • am-cor vs. Re­in­forced Con­crete and Block­work = As Strong/Stronger.
    • Re­in­for­cing bars are not stiff by them­selves, but will bend un­der their own weight; by them­selves they will not hold up a build­ing.
    • Bar spa­cing is of­ten 2" (5cm) to 6" (15cm) apart; the con­crete between such bars is ac­tu­ally dead weight, since it re­ceives no help from the bar to with­stand ten­sion.
    • Fail­ure in a re­in­forced con­crete build­ing is of­ten due to the ex­cess­ive weight of the struc­ture it­self, and its in­ab­il­ity to res­ist crack­ing.
    • am-cor light weight gal­van­ized steel frame mem­bers are stiff yet flex­ible; they will not bend un­der their own weight, and they can hold up an en­tire build­ing.
    • am­cor­ite Ferrocement struc­tur­al skins are thin and light, there is no ce­ment more than 1/8" (3mm) away from Car­bon steel re­in­for­cing
    • An am-cor build­ing will not col­lapse un­der its own weight, even un­der ex­treme load­ing con­di­tions; in­stead, it the unibody stress skin will flex, where­as a re­in­forced con­crete build­ing would crack and fail, or even worse, col­lapse.
  • am-cor vs. Struc­tur­al Steel = As Strong/Stronger.
    • The am­cor­ite Fer­ro­cement skin pro­tects its in­ner steel frame­work from rup­ture, and strengthens it against bend­ing.
    • The com­pat­ib­il­ity of steel and ce­ment are max­im­ized in the am-cor uni­fied com­pos­ite struc­ture, where steel and ce­ment are keyed to­geth­er as well as bon­ded to­geth­er, cre­at­ing a unibody shell.
    • This com­pos­ite as­sembly in­creases res­ist­ance of each mem­ber by join­ing them all to­geth­er, not just with bolts, but along the en­tire length of every steel pro­file.
    • The com­pos­ite am-cor as­sembly con­fig­ur­a­tion in­creases the strength of the steel frame, by adding the com­press­ive strength of ce­ment. Again, an am-cor Fer­ro­cement struc­ture will flex, where­as a struc­tur­al steel's con­nec­tions between com­pon­ents will fail.
Also see:

What are the fire ratings for the am-cor System?

We're fully fire rat­ing com­pli­ant:
  • UL 2-hour as­sembly: am-cor walls and ceil­ings coated on one side with am­cor­ite Fer­ro­cement mix
  • UL 4-hour as­sembly: am-cor walls and ceil­ings coated on both sides with am­cor­ite Fer­ro­cement mix
Stand­ard fire re­tard­ing as­sem­blies (e.g.: fire-rated gypsum) can also be in­stalled in­creased pro­tec­tion.
See our Code Compliance page for de­tails.

What R-Value / U-Value does the am-cor System have?

The am-cor Sys­tem is a struc­tur­al sys­tem, and does not in­clude in­su­la­tion. The Fer­ro­cement skin has an R value of 0.6.

Why we don't in­clude any one par­tic­u­lar in­su­la­tion as part of the sys­tem:

  • Design­ing your struc­ture around your in­su­la­tion choice is a Bad Idea™. In­su­la­tion tech­no­logy is con­stantly im­prov­ing; why con­strict your build­ing's design to an in­su­la­tion type?
  • The am-cor Sys­tem al­lows for much more flex­ib­il­ity than oth­er sys­tems which man­date an in­su­la­tion type (e.g.: SIPS, ICF).
  • The cav­ity (hol­low) walls, floors, and roofs of the am-cor Sys­tem al­low for any type and depth of in­su­la­tion, from high per­form­ance poly­iso­cy­a­nur­ate & aero­gel as­sem­blies, to very green & low VOC in­su­la­tions.
  • Stand­ard North Amer­ic­an am-cor Kits range from 6" (15cm) wall cav­it­ies to 8" (20cm) & 12" (30cm) wall, floor & roof cav­it­ies.
  • De­pend­ing on your needs, you can achieve R100 or Pass­ive Haus rat­ings with the right as­sembly, such as double wall designs & high per­form­ance thermal breaks.
Photologue Photo - 1164
See also:

Do I need formwork for my floor slabs?

No. Your am-cor Kit's ex­ter­i­or wall pan­els act as the slab form­work. See also:

Are am-cor flat roofs really flat?

No. Our "flat" roofs are al­ways slightly sloped for drain­age.

How are windows & doors installed?

am-cor pre­fab Wall Pan­els are framed with open­ings sized to ac­cept your spe­cified win­dows and ex­ter­i­or doors.

To mount open­ings in the wall pan­els, per­form the fol­low­ing pro­ced­ure on site, after pan­els have been fastened in place, and be­fore coat­ing with amcorite Ferrocement struc­tur­al skin:
  • Un­fasten the Car­bon steel ex­pan­ded met­al sheath­ing around the win­dow and door jambs.
  • Tem­por­ar­ily pull back the Car­bon steel mesh.
  • Place the win­dow or door in­to the open­ing, with its nail­ing fin against the steel frame jambs, sills, and heads of each open­ing.
  • Fold the sheath­ing back in place, and fasten the win­dow to the frame, through both sheath­ing and nail­ing flange.
  • Usu­ally open­ings are sized to leave a 1/2" (1-2cm) gap between win­dow/door unit and frame, to al­low an in­teri­or dry­wall re­turn around open­ings.
  • If this is the case in your am-cor Kit, place a shim of 1/2" dry­wall, ply­wood, or aero­gel thermal break, between the unit and the frame when mount­ing the unit, to en­sure an even gap right around the in­teri­or face.
This pro­ced­ure and oth­ers are covered in the Field Manu­al in­cluded with each am-cor Kit.  See Kit Contents and Construction Sequence for more.

Do am-cor walls need housewrap?

No. When prop­erly in­stalled, the am-cor Ferrocement struc­tur­al skin is seam­less and should not al­low air in­filt­ra­tion.

A good in­sur­ance is to in­stall at least a skim coat (2" or 5cm) of closed-cell spray foam in­su­la­tion (e.g.: poly­iso­cy­a­nur­ate), which will fill in mi­cro­scop­ic cracks and act as a va­por bar­ri­er. Cus­tom­ers who have con­struc­ted "tight" houses have had suc­cess with this meth­od.

An­oth­er pop­u­lar meth­od is to use a good, weath­er-res­ist­ant syn­thet­ic stucco as a fin­ish coat, thereby adding an­oth­er lay­er of pro­tec­tion.

See also:

What's the difference between a structural stucco coat & a finish coat?

The am­cor­ite Port­land ce­ment and sand Ferrocement struc­tur­al coat is the first coat­ing to be ap­plied to your am-cor gal­van­ized steel frame build­ing shell upon com­ple­tion of pan­el place­ment.  This struc­tur­al coat is mixed ac­cord­ing to your am-cor Field Manu­al, and forced through the Car­bon steel ex­pan­ded met­al mesh sheath­ing on the fact­ory pre­fab­ric­ated am-cor steel frame pan­els. In for­cing the am­cor­ite mix through the small holes in the ex­pan­ded met­al you are uni­fy­ing two com­pat­ible ma­ter­i­als: ce­ment and steel, to cre­ate a single com­pos­ite struc­ture. This unibody struc­tur­al coat cre­ates a seam­less skin which joins all pan­els and steel frame mem­bers to­geth­er in­to a single ce­men­ted piece. This ac­tion cre­ates am-cor's re­dund­ant, life sav­ing struc­tur­al shell.

If your build­ing's ex­ter­i­or fin­ish is a stucco sur­face, we call this the fin­ish coat.
This second (or op­tion­ally third) coat is usu­ally a stand­ard ce­ment and sand stucco mix, which is thinly ap­plied to smooth out any vari­ations in the am­cor­ite struc­tur­al coat. This coat can be a mix­ture of Weath­er res­ist­ant white Port­land ce­ment, tin­ted and tex­tured for ap­pear­ance, or com­mer­cial weath­er res­ist­ant ce­ment or syn­thet­ic mix­tures may be used as well.

Ad­di­tion­al coats may be ad­ded to cre­ate or­na­ment­al re­lief on walls such as: trim, cor­nices, quoins, key­stones, sills, etc. Trim is of­ten fin­ished in a dif­fer­ent col­or and tex­ture from the wall sur­face for ac­cent.

Do I need to drill for wires & pipes?

No. Pre­fab­ric­ated am‑cor pan­els in­clude wall studs, floor joists, and roof rafters, which are fact­ory punched to al­low fast and easy in­stall­a­tion of ser­vice runs. Plastic grom­mets are provided with your Kit. Place the grom­mets in the fact­ory punched holes, then run your pipes and wires through the grom­mets, to avoid chaf­ing on the gal­van­ized steel.

See also:

What kind of interior insulation should I use?

Over the years, our cli­ents have in­stalled a num­ber of dif­fer­ent types of in­teri­or in­su­la­tions, from just fiber­glass batts, to to 10" (25cm) sol­id of closed cell spray foam. Our cur­rent fa­vor­ite bal­ance between per­form­ance & ex­pense is a com­bin­a­tion of:

  • At least 2" (5cm) skim coat of poly­iso­cy­a­nur­ate spray foam in­su­la­tion (va­por-bar­ri­er),
  • High-per­form­ance aero­gel thermal breaks,
  • Low-VOC "eco" batts,
  • Low-VOC blown cel­lu­lose.
For the price, this com­bin­a­tion per­forms quite ad­equately in walls, in­ter­me­di­ate floors, and roofs. It's not too ex­pens­ive nor dif­fi­cult to in­stall. In colder cli­mates, one op­tion for ad­di­tion­al per­form­ance is a double-wall, sep­ar­ated by thermal breaks (in some cases, just slight a slight fur­ring out is re­quired for a reas­on­able per­form­ance gain).

See also:

Can EIFS be used over am-cor Ferrocement surfaces?

Yes. EIFS (Ex­ter­i­or In­su­la­tion and Fin­ish­ing Sys­tems) can be used with the am-cor Sys­tem. To the EIFS in­staller, the Fer­ro­cement struc­tur­al skin is the same as a poured con­crete or con­crete block wall sur­face.

Is experienced labor required for am-cor construction?


Con­tract­ors & Build­ers
You don't need to rely on highly-skilled, but ex­pens­ive trades­men. Our pre­fab Kits provide the busi­ness op­por­tun­ity for build­ers and con­tract­ors to:
  • Per­form work faster & col­lect pay­ment soon­er
  • Bid com­pet­it­ively
  • Greatly re­duce site time & labor
  • Gen­er­ate great­er & faster per­form­ance from build­ing crews
  • Do more work in less time = great­er net in­come
  • Lower site over­head costs: no cut­ting, no meas­ur­ing, no cart­age fees, no shell con­struc­tion waste
  • High­er profit mar­gins: con­sist­ently high qual­ity and life-safe build­ings at low cost
The am-cor Field Manu­al is easy to read, fully il­lus­trated, and is a great help to the su­per­visor. He does not need to pore through com­plic­ated ar­chi­tec­tur­al & en­gin­eer­ing draw­ings in or­der to as­semble the build­ing struc­ture.
This leads to:
  • great­er field ef­fi­ciency
  • less chance of er­ror
  • high­er pro­duc­tion levels
  • pre­dict­able cost
Please see our Professionals sec­tion for more in­form­a­tion.

If you are in­ex­per­i­enced with nor­mal con­struc­tion meth­ods you can still suc­cess­fully as­semble and coat your am-cor Kit.  No meas­ur­ing or cut­ting is re­quired.
Your Field Manu­al has a full de­scrip­tion of the Construction Sequence, as well as de­tailed il­lus­trated in­struc­tions on how to line out your build­ing, ex­cav­ate, pour foot­ers and con­crete floor slab, etc.

Check out our DIY sec­tion for more.

am-cor Kit as­sembly is easy, fast, and fun. am-cor pre­fab­ric­ated pan­els are light weight and clearly marked. Their po­s­i­tions are shown on the Pan­el Place­ment Dia­grams of your am-cor Field Manu­al.

Coat­ing the as­sembled pan­el Kit with am­cor­ite Fer­ro­cement mix­ture is done either with by trow­el or spray. DIY ap­plic­at­ors quickly be­come pro­fi­cient with either meth­od.

Sub­con­tract­ors usu­ally in­stall roof­ing, in­su­la­tion, dry­wall, elec­tric­al, plumb­ing, and mech­an­ic­al ser­vices; however, you can pur­chase how-to books on the in­ter­net and at build­ing sup­ply stores, to learn these trades as well.

How are openings flashed?

Re­quire­ments for flash­ing vary de­pend­ing on re­gion & loc­al code. The gen­er­al rule of thumb is: you should flash open­ings however they are nor­mally flashed in your re­gion, de­pend­ing the build­ing's ex­ter­i­or sur­face.
In this re­spect, the am-cor Sys­tem is no dif­fer­ent from stand­ard light gauge steel fram­ing.

The typ­ic­al meth­od:

  • Once win­dow and ex­ter­i­or door units are in­stalled in the am-cor Pan­els' gal­van­ized steel frame, and be­fore coat­ing with amcorite Ferrocement,
  • Po­s­i­tion flash­ing along the top of ex­ter­i­or open­ings and se­cure it with self tap­ping screws.
  • Mask doors & win­dows be­fore am­cor­ite ap­plic­a­tion
  • Coat the wall pan­els with the am­cor­ite/Port­land ce­ment/sand mix.
  • Flash as nor­mal, with your fin­ish sur­face (brick, stucco, stone, sid­ing, etc.)
If the ex­ter­i­or sur­face is an­oth­er stucco coat, do the fol­low­ing after com­plet­ing the above steps:
  • Make a V-shaped groove in the stucco along the head of the win­dow/door unit.
  • The fin­ish coat is not to cov­er this V. The un­fin­ished V al­lows any va­por between the am­cor­ite ce­ment coat and the fin­ish coat to es­cape, rather than be trapped at the win­dow/ex­ter­i­or door head.
This pro­ced­ure and oth­ers are covered in the Field Manu­al in­cluded with each am-cor Kit. Contact us if you have ques­tions on a spe­cif­ic in­stall­a­tion or pro­ject.

For in­creased thermal per­form­ance, open­ings can also be flashed and in­su­lated at the same time, and covered with a weath­er-res­ist­ance stucco fin­ish.
Photologue Photo - 916

Do I need to run electrical wires in BX cable?

No. BX cable, aka ar­mored cable or met­al sheathed wire, is not ne­ces­sary in am‑cor Kits. Elec­tric­al con­duit is also not re­quired.
The am‑cor System con­forms to the IBC, IRC, and NEC, which do not re­quire ar­mored cable in steel studs if grom­mets are in­stalled be­fore run­ning elec­tric­al wire through stud ser­vice holes. am‑cor Kits come stand­ard with grom­mets, just so you don't have to worry about this!

Do I need to frame out on the interior for services/finishes?

No. The Ferrocement skin of an am‑cor wall goes on the ex­ter­i­or of the pan­el, leav­ing the in­teri­or hol­low for run­ning ser­vices and ap­ply­ing fin­ishes.
Photologue Photo - 1149 Photologue Photo - 1150

No "Floating Corners"
You wont have ex­tra/re­medi­al work on the in­teri­or be­fore in­stalling elec­trics, plumb­ing, in­su­la­tion, and dry­wall. For ex­ample: all wall, ceil­ing, and floor corners and pan­el junc­tions are pre­framed; you won't come to a corner and find noth­ing to screw to!

See also:

Do I need a crane?

For light res­id­en­tial: No.
For multistory com­mer­cial/mul­ti­fam­ily: Not re­quired, but it helps speed things along.

am‑cor Pan­els (wall, floor, roof, etc.) are de­signed to be placed by 2 able-bod­ied people. Pan­els are fab­ric­ated from light­weight car­bon steel, so they're eas­ily trans­por­ted, and do not re­quire a crane.
Photologue Photo - 1152 Photologue Photo - 1153

However, if you have a large pro­ject with mul­tiple floors, con­sider us­ing a crane to quickly place the pan­els on the next story. If you have a big pro­ject, you'll most likely use a crane for mov­ing oth­er ma­ter­i­al as well (e.g.: dry­wall, etc.).

How are air barriers installed in an am‑cor structure?

Gen­er­ally, your am‑cor build­ing has a num­ber of air bar­ri­er as­sem­blies, which con­form to the rel­ev­ant ASTM standards:
  • The amcorite Ferrocement unibody ex­ter­i­or skin forms a con­tinu­ous bar­ri­er, elim­in­at­ing air in­filt­ra­tion around your walls, floors, found­a­tion, and roof (if a Fer­ro­ce­ment roof).
  • We re­com­mend a wa­ter-res­ist­ant ex­ter­i­or fin­ish coat­ing over the struc­tur­al Fer­ro­ce­ment skin, for ad­ded pro­tec­tion.
  • We re­com­mend the Su­per level of Insulation for walls & roofs. This in­cludes at least 2" (5cm) of closed cell foam in­su­la­tion, form­ing a con­tinu­ous in­teri­or air & va­por bar­ri­er, and cov­er­ing all wall/roof/floor in­ter­sec­tions.
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Don't stucco homes have cracking problems?

You're prob­ably fa­mil­i­ar with stucco fin­ishes over wood fram­ing. This par­tic­u­lar meth­od of con­struc­tion has un­for­tu­nately giv­en stucco ex­ter­i­ors an un­war­ran­ted re­pu­ta­tion in the USA over the past few dec­ades.

Crack­ing and struc­tur­al prob­lems in wood & stucco build­ings is dir­ec­tly re­lated to mois­ture and the in­com­pat­ib­il­ity of these two ma­ter­i­als: the build­ing's wood frame ex­pands and con­tracts at a dif­fer­ent rate than the stucco ex­ter­i­or. The prob­lem is ex­acer­bated by mois­ture, as the build­ing's wooden struc­ture will swell, rot, and even­tu­ally dis­in­teg­rate.

Since steel and ce­ment have ap­prox­im­ately the same thermal ex­pan­sion coef­fi­cient, we don't have these is­sues. The old­est am‑cor Fer­ro­Ce­ment struc­ture is ap­prox­im­ately 20 years old, with no re­por­ted prob­lems.

Do you use expansion joints?

We spe­ci­fy ex­pan­sion joints with the same re­quire­ments as stand­ard con­crete con­struc­tion, at ap­prox­im­ately every 120 lin.ft. (36.5m) of wall.

How is continuous insulation installed in an am‑cor structure?

In or­der to meet ASHRAE re­quire­ments for con­tinu­ous in­su­la­tion, you have a num­ber of op­tions.

Cus­tom­ers have ac­com­plished tight, con­tinu­ous in­su­la­tion in am-cor build­ings by us­ing as­sem­blies de­tailed un­der Su­per and Passiv in our In­su­la­tion sec­tion.
Also, am-cor Exo­Struc­tures can wrap the ex­ter­i­or of an ex­ist­ing build­ing in a com­plete weath­er­proof, struc­tur­al and in­su­lat­ing Fer­ro­cement bar­ri­er.

Poor Man's PassivHaus

The Su­per Wall & Su­per Roof as­sem­blies, aka the "Poor Man's PassivHaus", provide ex­cel­lent in­su­la­tion per­form­ance for a min­im­al price in­crease: the build­ing's struc­ture is com­pletely sep­ar­ated by thermal breaks from in­teri­or con­di­tioned space. See these as­sem­blies and more in our In­su­la­tion sec­tion.

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