▁they ▁are ▁made ▁from : ▁wood , ▁steel , ▁fi berg lass , ▁UP VC / vin yl , ▁al umin um , ▁composite , ▁glass ▁( pat io ▁doors ). .. ▁ ▁Wood en ▁doors ▁– ▁including ▁solid ▁wood ▁doors ▁– ▁are ▁a ▁top ▁choice ▁for ▁many ▁home own ers , ▁largely ▁because ▁of ▁the ▁a est h etic ▁qual ities ▁of ▁wood . ▁Many ▁wood ▁doors ▁are ▁custom - made , ▁but ▁they ▁have ▁several ▁down s ides : ▁their ▁price , ▁their ▁maintenance ▁requirements ▁( regular ▁painting ▁and ▁st aining ) ▁and ▁their ▁limited ▁ins ulating ▁value ▁( R - 5 ▁to ▁R - 6 , ▁not ▁including ▁the ▁effects ▁of ▁the ▁glass ▁elements ▁of ▁the ▁doors ). ▁Wood ▁doors ▁often ▁have ▁an ▁over hang ▁requirement ▁to ▁maintain ▁a ▁war rant y . ▁An ▁over hang ▁is ▁a ▁roof , ▁por ch ▁area ▁or ▁aw ning ▁that ▁helps ▁to ▁protect ▁the ▁door ▁and ▁its ▁finish ▁from ▁U V ▁ray s . ▁ ▁Ste el ▁doors ▁are ▁another ▁major ▁type ▁of ▁resident ial ▁front ▁doors ; ▁most ▁of ▁them ▁come ▁with ▁a ▁poly ure th ane ▁or ▁other ▁type ▁of ▁fo am ▁ins ulation ▁core ▁– ▁a ▁critical ▁factor ▁in ▁a ▁building ' s ▁overall ▁comfort ▁and ▁efficiency . ▁Ste el ▁doors ▁mostly ▁in ▁default ▁comes ▁along ▁with ▁frame ▁and ▁lock ▁system , ▁which ▁is ▁a ▁high ▁cost ▁efficiency ▁factor ▁compared ▁to ▁Wood en ▁doors ▁ ▁Most ▁modern ▁exterior ▁walls ▁are ▁designed ▁to ▁provide ▁thermal ▁ins ulation ▁and ▁energy ▁efficiency ,