The In­stal­la­tion

When it comes to per­for­mance and the good looks of your tim­ber cladding, the han­dling, stor­age and in­stal­la­tion are just as im­por­tant as the spec­i­fi­ca­tion

Homebuilding & Renovating - - PROJECT ADVICE -

Han­dling and Stor­age

Care should be taken when han­dling and stor­ing cladding boards on site prior to be­ing fixed. The boards must be pro­tected from mois­ture, sun­light, dirt, scratch­ing and me­chan­i­cal dam­age, and should not be left in con­tact with the ground. Boards should be stacked on tim­ber bear­ers with the top of the pack cov­ered to pro­tect against rain­fall, left open at the sides al­low­ing air to cir­cu­late freely and with the ex­ter­nal sur­face of the boards face down. Cladding should ide­ally be fixed within two weeks of de­liv­ery, so es­tab­lish­ing your sup­plier’s lead-in time and pro­gram­ming this ac­cord­ingly into your build is a very good idea.


Your struc­tural war­ranty provider or ar­chi­tect/sur­veyor en­gaged to pro­vide a cer­tifi­cate ac­cept­able to your mort­gage com­pany will in­sist on a ven­ti­la­tion gap be­hind the tim­ber cladding which should be a min­i­mum of 19mm (but I would rec­om­mend 25mm). Low and high level ven­ti­la­tion is re­quired, be­hind the al­low­ing cladding, the en­abling free flow it to of dry air out af­ter hav­ing been ex­posed to rain or snow; this will also im­prove the life­span of the cladding. Par­tic­u­lar care has to be taken above and be­low win­dow and door open­ings to en­sure ad­e­quate low and high level ven­ti­la­tion is pro­vided at th­ese points. Anti-in­sect/ ver­min mesh should be fit­ted at both the low and high ven­ti­la­tion points.

De­tail­ing at Open­ings

As with all forms of cladding, the devil is in the de­tail at per­fo­ra­tions or changes of di­rec­tion in the cladding and it is im­per­a­tive that you/your ar­chi­tect/ cladding sup­plier agree the de­tails for th­ese ar­eas so that the cor­rect ma­te­ri­als are sup­plied ac­cord­ingly. Do en­sure that the trades­peo­ple em­ployed to fit the cladding are given a copy of the de­tails and ad­vised that they have to be strictly fol­lowed.


How the tim­ber cladding is fixed is fun­da­men­tal to its long-term per­for­mance both in terms of ap­pear­ance and dura­bil­ity. In my ex­pe­ri­ence, a large per­cent­age of detri­men­tal is­sues with cladding are due to the tim­bers be­ing in­cor­rectly fixed. I would rec­om­mend us­ing the best avail­able grade of stain­less steel nails/ screws in or­der to elim­i­nate cor­ro­sive leach­ing, which is very un­sightly and can com­pletely spoil the look of the cladding. It is im­por­tant that the nail/ screw is not over­driven into the board, as this will pro­duce a ‘ bul­let-hole’ ef­fect which may com­pro­mise the dura­bil­ity of the board; ide­ally the head of the nail/screw should fin­ish flush to the tim­ber prevent­ing wa­ter ingress at the point of fix­ing. Screw fix­ing gen­er­ally gives a bet­ter end re­sult as more care is taken in po­si­tion­ing and fin­ish­ing the screw head flush with the tim­ber sur­face. In or­der to pre­vent split­ting at the board ends, pre-drilling is rec­om­mended for cer­tain species of tim­ber, or al­ter­na­tively you could use one of the pro­pri­etary screws on the mar­ket that boast no pre-drilling be­ing nec­es­sary due to their unique de­sign, thus sav­ing time on site.

Hor­i­zon­tal and Ver­ti­cal Cladding

For hor­i­zon­tal cladding for tim­ber frame and ma­sonry builds, ver­ti­cal reg­u­larised treated tim­ber bat­tens, a min­i­mum 25 x 50mm (form­ing a 25mm ven­ti­la­tion cav­ity), should be fixed at a max­i­mum of 600mm cen­tres to which the tim­ber cladding is then fixed. Boards should al­ways be joined on a ver­ti­cal bat­ten, with the joints be­ing stag­gered. The bot­tom edge of the bot­tom board should be cham­fered to al­low wa­ter to run off freely. The same goes for ver­ti­cal cladding, ex­cept that hor­i­zon­tal bat­tens, a min­i­mum 25 x 50mm at a max­i­mum of 600mm cen­tres, are then fixed to the ver­ti­cal bat­tens and in turn the tim­ber cladding is fixed. Ver­ti­cal cladding should al­ways be fixed with the growth rings point­ing down­wards and the bot­tom edge of the boards should again be cham­fered to al­low wa­ter to run off freely. Cladding should ide­ally be kept 300mm above the fin­ished ground level and never less than 150mm, to avoid ‘splash stain­ing’ caused by heavy rain­fall on bare soil and mois­ture ab­sorp­tion by the cladding when there is ex­ces­sive snow­fall.


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