PIR boards , what is the best application HELP !

irishlion

Registered User
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ok guys here goes , would love some advice from people who know best !

recently purchased a cottage which was originally built in the 1940's . of course , back then , DPC's never existed so we knew we would probably have a rising damp issue .... after our surveyor did his thing , he agreed ....

to make quite a long painful story short ive stripped all external walls of previous owners plasterboards , fiber glass insulation , studding , and have also kango'd off up to a height of 1.2 meters all skimcoat and scratchcoats revealing the solid 9 by 18 brick work .........

so here is where im at right now , im getting all the external walls injected with a DPC , and also getting the lower part of the walls tanked with the 3 layers of plaster containing the chemicals needed bringing the walls back to a respectable flush condition . we have purchased 80mm PIR boards for the living room , and 40mm boards for the two smaller bedrooms .

it was suggested to me , to basically have independent studded walls set in place , independent at least below 1.2 meters as you cannot fix anything through the new tanking , and fix above that if needed . then , to cut up the PIR boards into different sizes and fit them between the studding and noggins in a jigsaw like fashion .... the taping the edges with the special foil / metal type thermal tape right along each wall . i was slightly worried when i heard this thinking that what if the tape lost some of its stickyness etc over the years or how thermal could that possibly be with the front side of battons and noggins exposed ? .... anyhow , then fix foil backed plasterboard to the studding and skim ... oh , and services to be dropped in the void behind the tapped PIR's and wall . so what do you think so far ?
it sounded good to me until i checked out the website of the boards and now im totally conflustered !!!!!!!!!!!

they say to basically rest the board , whole , untouched or torn against the external wall , internally of course . do so right along the wall and obviously make cuts for windows etc . THEN , have your independent studding placed up against the boards , sole plates fixed top and bottom , tape all seams between the boards and then fix your plasterboards to the independent studding and use the void between PIR board and plasterboard for services ......

this sounds like the proper job to me , but im worried that the boards are basically right against the walls which suffer from rising damp . i mean yes , im getting them treated , but what if it comes back ? and what about the ventilation between boards and original wall which was suggested in the first idea ??

im really keen to get this spot on for many reasons , and i guess , its a case of do it once right , job done . id die after all this , that it didnt prove to be the right route to take so i would love to hear from the people who know best , what to do ...

many thanks in advance

G .
 
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