Page:Once a Week Jul - Dec 1859.pdf/532

17, 1859.] whole space  occupied  by  the  buildings. So then the buildings  are  to  be  cleared  away  to  convert the whole  city  into  a garden? Not so,  only  the roofs of  the  buildings.

In southern  climates  buildings  are  constructed with flat  roofs,  as  there  is  no  snow,  and  comparatively little  rain. In some  cases  the  roof consists of  a floor  of  canes  or  sticks,  covered  with mud mixed  with  chopped  straw. In South America, La  Plata,  where  mist  and  heavy  rain fall at  times,  flat  roofs  are  constructed  by  laying first parallel  stems  of  palm-trees  from  wall  to  wall, filling the  crevices  with  sticks  and  mud,  laying thereon flat  tiles  cemented  with  a mixture  of  lime, burnt brick  dust,  and  blood; covering  the  joints with a second  layer  of  tiles,  and  then  again  with a third layer. This is  impervious  to  water; and as there  are  no  heavy  carts  or  waggons  to  induce vibration, this  kind  of  roof  does  not  crack. Roofs depart further  from  the  horizontal  and  grow  more vertical as  we  go  north; and  in  Canada  they get to  a steeple  form,  like  that  of  Westminster Abbey’s mountain  ridge. Almost too  steep  for tiling, they  use  small  oblong  boards,  called  shingles, nailed  on  to  them,  or  they  are  covered  with tin plates,  which  glisten  like  eastern  minarets  in the  sunshine. On such  roofs  snow  cannot  lie; three inches  thickness  of  snow  slides  off  in  a kind of small  avalanche,  to  the  annoyance  of  the passers by.

Steep roofs  are  necessarily  lofty,  and  are  much exposed to  damage  by  wind; and  what  are  called Italian roofs,  of  much  less  fall,  are  therefore largely used; but  the  steep  roofs  are  truncated  in various  ways — the  apex  is  sometimes  cut  off  flat, or the  height  is  lessened  by  making  the  roof  in  a series  of  ridges  of  the  same  pitch,  with  valleys between them  and  around  them,  involving  risk  of the  very  snow  they  are  pitched  to  avoid,  by  the overflowing of  the  gutters,  which  are  a receptacle of the  ashes  that  pass  up  the  chimneys. Smoke nuisance thus  helps  to  increase  rain  nuisance. Italian roofs,  with  external  gutters,  are  not  exposed to this; but  they  involve  the  difficulty,  that  if  a slate  gets  loose,  the  trampling  of  those  who  have to repair  it  breaks  many  other  slates,  and  at  a risk  of  the  repairer  falling  off  the  house.

To get  access  to  ordinary  roofs  for  the  purpose of repairs,  there  is  usually  a trap-door  in  the  attic ceiling, where  a ladder  is  placed  on  occasion. In the roof  itself  is  another  trap-door  or  a dormer, leading out  into  a gutter  so  narrow  that  one  cannot walk along  it  without  disturbing  the  tiles  or slates. Apart from  the  dirt  and  overflowing  of the  gutters,  these  roofs  are  rarely  in  order; and the space  below  the  tiles,  called  the  “cockloft” — probably from  having  been  a roosting  place for the  fowls  in  the  buildings  forming  the  type of the  present  structures — is  a receptacle  for  soot, dust, filth,  and  all  the  bad  air  in  the  house  ascending from  below: add  to  this,  it  is  usually  all  in darkness. Few persons  know  what  this  really  is, till in  case  of  fire,  when  they  know  not  how  to escape,  and  risk  their  lives  in  slipping  from  steep gutters on  their  way  to  a neighbouring  house. Those who  have  ascended  the  dark  wooden  gallery in passing  through  the  dome  of  St.  Paul’s,  may have an  idea  of  it,  save  that  they  ascend  staircases instead of  ladders. Thus a space  equal  to  nearly the whole  basement  area  of  all  the  buildings  in London  is  devoted  to  filth  and  risk  of  life,  and  au incalculable  amount  of  waste  in  repairs.

This great  nuisance  has  not  passed  by  unnoticed. The space  alone — equal  to  another  floor  in  a house — is wasted,  and  this  space — supposing  the  air  to  be free  from  smoke — is  the  purest  in  the  whole  house, being farthest  removed  from  the  surface  of  the earth. Attempts have  been  made  to  construct flat roofs,  but  rarely  successfully. An architect once showed  me  his  own  dwelling,  over  a part  of which  he  had  a flat  roof,  which  he  boasted  was successful. But in  every  corner  there  was  a stain, and at  last  he  was  obliged  to  own  that  the  cement would crack  from  time  to  time,  and  required  constant attention.

The reason  is  plain. All flat  roofs  hitherto constructed have  been  of  brittle  material,  and brittle material— such  as  water-cement — cracks from subsidence  of  the  ground; from  unequal settlement, from  expansion  and  contraction  by heat  and  cold,  and  from  many  other  causes.

To guard  against  this,  flat  roofs  are  commonly covered with  sheet-lead. But this  again  is  a nuisance. To prevent  the  lead  from  cracking  by the  heat  and  cold,  it  is  laid  in  broad  stripes,  the edges being  turned  over  projecting  rolls  of  timber, sufficiently elevated  to  prevent  rain-water  from overflowing. We find  every  alternate  ridge  is  a table-elevation,  or  a valloy,  then  a succession  of valleys. Such a roof  is  a nuisance  to  walk  on, independently of  the  temptation  to  thieves  to  steal the lead.

Is it  then  impossible  to  make  flat  and  permanent roofs — roofs permanent  as  a foot-pavement? I think — nay, I’m  sure,  it  is  not  a difficult  operation if  set  about  with  common  sense. We have for ages  made  flat  roofs  to  ships  at  sea — I mean the decks. Planks nailed  down  side  by  side  are caulked with  tarred  or  pitched  hemp. The planks are wet  naturally  in  some  climates  and  artificially in others,  and  their  constant  swelling  keeps  the joints tight. We put  wine  and  liquors  into  barrels — the wine  swells  the  staves  and  the  liquor  does not run  out. We put  wine  and  liquors  into stone bottles,  and  we  joint  the  opening  with  an elastic  cork — the  cork  swells  and  the  liquor  does not run  out. The difference  between  these  arrangements and  that  of  the  flat  roofs  that  let  in  water is, that  in  the  one  case,  the  materials  are  elastic, in the  others,  brittle.

For many  years  past  a valuable  building  material has  been  in  use; slate  sawn  or  cut  into  large tables of  any  required  size,  from  half  an  inch  to  three or four  inches  in  thickness. If we  suppose  four walls to  be  built  up  in  a square  and  overlaid  with a solid table  of  this  slate,  projecting  a foot  beyond the walls,  and  with  a descending  edge  to  prevent water running  underneath  to  the  walls,  it  is evident  that  nothing  short  of  a Swiss  flood  descending the  Rhine,  and  rising  upwards,  could  get access by  way  of  the  roof.

But we  can’t  get  slates  so  large! No! But we can  get  very  large  slates,  and  we  can  put  them together so  as  to  be  water-tight.

How?

As we  joint,  wine-bottles  with  corks; cork  the