Tyvek or fanfold underlayment when residing

Old 01-14-07, 11:53 AM
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Tyvek or fanfold underlayment when residing

We are residing our 1974 brick and cedar house with insulated vinyl siding and are unsure about whether to use Tyvek or a fanfold underlayment. If we remove the cedar siding first, should we put up Tyvek or the fanfold? What if we decide to keep the cedar and just go over it? Thanks for any advice?
Old 01-14-07, 12:03 PM
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Tyvek or fanfold underlayment when residing

If you remove the cedar siding install Tyvek. Pay particular attention to flashing and weatherproofing around the windows (especially the top). Vinyl siding is not a weather barrier and only sheds rain without wind.

If you leave the cedar siding on, you may have to use the fanfold to provide a smooth surface to install over. You could encounter appearance/installation problems at windows and doors because of the increased thickness. The fanflod only gives you a minimal, if any, increase in insulation because of gaps and open seams.


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