Even if your crawlspace is dry! You still want to wear a Tyvek suit and a Disposable Respirators. We prefer 3M N95 Disposable Respirator w/ Valve because the valve allows for fresh air exchange. Home Depot sells a Tyvek Suit for about $10.00 that are waterproof and have a hood. Well worth the money. Crawlspace work is stressful and you want to be comfortable and protect your body.