Section will be overlapped by header when come from another page

I have the following problem. What I want is when the user clicks in the navigation bar on "Contact" it will link to the contact page. This is a single page. When you are on contact and then clicking at the bottom of the page on, for example "Over ons" it should be redirect to the homepage (single page) and stop at that section. This works, but when you come from another page, the current section is overlapped by the header.

The jQuery code will not use the offset of the header, only when you are navigation inside the index.html.

Is there a way to fix the issue, so the section will not be overlapped by the header?

Live example:

http://ift.tt/1KRmFou

jQuery code:

// An offset to push the content down from the top
    var offset = $('#header').outerHeight();

    $('#primary-navwrapper li:not(.prev-page, .next-page), .list-of-links li').find('a[href^="#"]').click(function(event) { 
        event.preventDefault();


        $('#primary-navwrapper li a').removeClass("current");
        $(this).addClass("current");

        var anchorId = $(this).attr("href");
        var target = $(anchorId).offset().top - offset;         


        $('html, body').animate({ scrollTop: target }, 500, function () {
            window.location.hash = anchorId;        
        });

    });



    function setActiveListElements(event){
        // Get the offset of the window from the top of page
        var windowPos = $(window).scrollTop();

        $('#primary-navwrapper li a[href^="#"]').each(function() { 
            var anchorId = $(this);
            var target = $(anchorId.attr("href"));

            var offsetTop = target.position().top - offset;

            if (target.length > 0) {

                if (target.position().top - offset <= windowPos && (target.position().top + target.height() + offset ) > windowPos) {

                    $('#primary-navwrapper li a').removeClass("current");
                    anchorId.addClass("current");
                }
            }

        });

    }

$(window).scroll(function() {
        setActiveListElements();
        //updateLocationHash();
    });