diff --git a/src/components/EstimateBuilder.tsx b/src/components/EstimateBuilder.tsx
index 9fbc50e..d80ffe2 100644
--- a/src/components/EstimateBuilder.tsx
+++ b/src/components/EstimateBuilder.tsx
@@ -51,7 +51,11 @@ const EstimateBuilder: Component<EstimateBuilderProps> = (props) => {
     const [showHistoryModal, setShowHistoryModal] = createSignal(false);
     const [showNewEstimateModal, setShowNewEstimateModal] = createSignal(false);
     const [showExportTableModal, setShowExportTableModal] = createSignal(false);
+    const [showCsvImportModal, setShowCsvImportModal] = createSignal(false);
     const [applyTemplateScopeId, setApplyTemplateScopeId] = createSignal<string | null>(null);
+    const [pendingCsvImportText, setPendingCsvImportText] = createSignal<string | null>(null);
+    const [excludedScopeIds, setExcludedScopeIds] = createSignal<string[]>([]);
+    const [excludedSubScopeIds, setExcludedSubScopeIds] = createSignal<string[]>([]);
 
     // 2. Initialize custom hooks/primitives
     const { selectedIds, setSelectedIds, lastSelectedId, setLastSelectedId, toggleSelection, clearSelection, copyColumnSum } = useSelectionManager();
@@ -191,7 +195,7 @@ const EstimateBuilder: Component<EstimateBuilderProps> = (props) => {
         return Number.isFinite(parsed) ? parsed : 0;
     };
 
-    const mergeCsvQuantities = (csvText: string) => {
+    const mergeCsvQuantities = (csvText: string, options?: { excludedScopeIds?: string[]; excludedSubScopeIds?: string[] }) => {
         const { items: extracted, ignored } = extractItemsFromCSV(csvText);
         appStore.setIgnoredLines(ignored);
 
@@ -221,8 +225,14 @@ const EstimateBuilder: Component<EstimateBuilderProps> = (props) => {
 
         let updatedExistingCount = 0;
         const matchedDescriptions = new Set<string>();
+        const excludedScopeIdSet = new Set(options?.excludedScopeIds ?? []);
+        const excludedSubScopeIdSet = new Set(options?.excludedSubScopeIds ?? []);
 
         const nextItems = items.map(item => {
+            const isExcludedByScope = item.scopeId ? excludedScopeIdSet.has(item.scopeId) : false;
+            const isExcludedBySubScope = item.subScopeId ? excludedSubScopeIdSet.has(item.subScopeId) : false;
+            if (isExcludedByScope || isExcludedBySubScope) return item;
+
             const key = normalizeDescription(item.description);
             const imported = importedByDescription.get(key);
 
@@ -252,15 +262,59 @@ const EstimateBuilder: Component<EstimateBuilderProps> = (props) => {
         setItems([...nextItems, ...newUnassignedItems]);
 
         const ignoredCount = ignored.length;
+        const excludedCount = excludedScopeIdSet.size + excludedSubScopeIdSet.size;
         const toastParts = [
             `Updated ${updatedExistingCount} item${updatedExistingCount === 1 ? '' : 's'}`,
             `added ${newUnassignedItems.length} unassigned`,
+            excludedCount > 0 ? `excluded ${excludedCount} selection${excludedCount === 1 ? '' : 's'}` : null,
             ignoredCount > 0 ? `ignored ${ignoredCount} row${ignoredCount === 1 ? '' : 's'}` : null
         ].filter(Boolean);
         setCopyToast(toastParts.join(' • '));
         window.setTimeout(() => setCopyToast(null), 3000);
     };
 
+    const toggleScopeExclusion = (scopeId: string) => {
+        const isExcluded = excludedScopeIds().includes(scopeId);
+        if (isExcluded) {
+            setExcludedScopeIds(prev => prev.filter(id => id !== scopeId));
+            return;
+        }
+
+        setExcludedScopeIds(prev => [...prev, scopeId]);
+        const subScopeIdsInScope = subScopes.filter(ss => ss.scopeId === scopeId).map(ss => ss.id);
+        if (subScopeIdsInScope.length > 0) {
+            setExcludedSubScopeIds(prev => prev.filter(id => !subScopeIdsInScope.includes(id)));
+        }
+    };
+
+    const toggleSubScopeExclusion = (subScopeId: string) => {
+        const isExcluded = excludedSubScopeIds().includes(subScopeId);
+        if (isExcluded) {
+            setExcludedSubScopeIds(prev => prev.filter(id => id !== subScopeId));
+            return;
+        }
+
+        setExcludedSubScopeIds(prev => [...prev, subScopeId]);
+    };
+
+    const closeCsvImportModal = () => {
+        setShowCsvImportModal(false);
+        setPendingCsvImportText(null);
+        setExcludedScopeIds([]);
+        setExcludedSubScopeIds([]);
+    };
+
+    const confirmCsvImport = () => {
+        const csvText = pendingCsvImportText();
+        if (!csvText) return;
+
+        mergeCsvQuantities(csvText, {
+            excludedScopeIds: excludedScopeIds(),
+            excludedSubScopeIds: excludedSubScopeIds()
+        });
+        closeCsvImportModal();
+    };
+
     const handleImportCsvQuantities = (e: Event) => {
         const input = e.currentTarget as HTMLInputElement;
         const file = input.files?.[0];
@@ -270,7 +324,10 @@ const EstimateBuilder: Component<EstimateBuilderProps> = (props) => {
         reader.onload = (event) => {
             const text = event.target?.result;
             if (typeof text === 'string') {
-                mergeCsvQuantities(text);
+                setPendingCsvImportText(text);
+                setExcludedScopeIds([]);
+                setExcludedSubScopeIds([]);
+                setShowCsvImportModal(true);
             }
         };
         reader.readAsText(file);
@@ -470,6 +527,102 @@ const EstimateBuilder: Component<EstimateBuilderProps> = (props) => {
             <ExportTableModal show={showExportTableModal()} onClose={() => setShowExportTableModal(false)} />
             <ApplyTemplateModal show={!!applyTemplateScopeId()} scopeId={applyTemplateScopeId()} onClose={() => setApplyTemplateScopeId(null)} />
             <HistoryModal show={showHistoryModal()} onClose={() => setShowHistoryModal(false)} onCheckout={checkoutVersion} />
+            <Show when={showCsvImportModal()}>
+                <Portal>
+                    <div class="fixed inset-0 z-[100] flex items-center justify-center bg-background/80 backdrop-blur-sm p-4 animate-in fade-in duration-200">
+                        <div class="bg-card w-full max-w-2xl rounded-3xl shadow-premium border border-border animate-in zoom-in-95 duration-200 overflow-hidden">
+                            <div class="p-6 border-b border-border/50 flex items-center justify-between bg-muted/20">
+                                <div>
+                                    <h3 class="text-xl font-black">Import CSV Quantities</h3>
+                                    <p class="text-[10px] text-muted-foreground font-black uppercase tracking-widest mt-1">Choose scopes or sub-scopes to leave unchanged</p>
+                                </div>
+                                <button onClick={closeCsvImportModal} class="p-2 hover:bg-muted rounded-xl transition-colors">
+                                    <X class="w-5 h-5 text-muted-foreground" />
+                                </button>
+                            </div>
+
+                            <div class="p-6 space-y-5 max-h-[70vh] overflow-y-auto">
+                                <p class="text-sm text-muted-foreground">
+                                    Matching items in excluded sections will keep their current quantities. Unassigned items are always eligible for updates.
+                                </p>
+
+                                <Show
+                                    when={scopes.length > 0}
+                                    fallback={
+                                        <div class="rounded-2xl border border-border bg-muted/20 px-4 py-5 text-sm text-muted-foreground">
+                                            No scopes exist yet. Import will only update unassigned items and add unmatched rows to the unassigned list.
+                                        </div>
+                                    }
+                                >
+                                    <div class="space-y-4">
+                                        <For each={scopes}>
+                                            {(scope) => {
+                                                const scopeSubScopes = () => subScopes.filter(ss => ss.scopeId === scope.id);
+                                                const isScopeExcluded = () => excludedScopeIds().includes(scope.id);
+
+                                                return (
+                                                    <div class="rounded-2xl border border-border bg-background overflow-hidden">
+                                                        <label class="flex items-start gap-3 px-4 py-4 border-b border-border/50">
+                                                            <input
+                                                                type="checkbox"
+                                                                checked={isScopeExcluded()}
+                                                                onChange={() => toggleScopeExclusion(scope.id)}
+                                                                class="mt-1 h-4 w-4 rounded border-border text-primary focus:ring-primary"
+                                                            />
+                                                            <div class="min-w-0">
+                                                                <div class="font-bold text-foreground">{scope.name}</div>
+                                                                <div class="text-xs text-muted-foreground">Exclude this entire scope from quantity replacement.</div>
+                                                            </div>
+                                                        </label>
+
+                                                        <Show when={scopeSubScopes().length > 0}>
+                                                            <div class={`px-4 py-3 space-y-2 ${isScopeExcluded() ? 'opacity-50' : ''}`}>
+                                                                <div class="text-[10px] font-black uppercase tracking-widest text-muted-foreground">Sub-scopes</div>
+                                                                <For each={scopeSubScopes()}>
+                                                                    {(subScope) => (
+                                                                        <label class="flex items-start gap-3 rounded-xl px-3 py-2 hover:bg-muted/30 transition-colors">
+                                                                            <input
+                                                                                type="checkbox"
+                                                                                checked={excludedSubScopeIds().includes(subScope.id)}
+                                                                                disabled={isScopeExcluded()}
+                                                                                onChange={() => toggleSubScopeExclusion(subScope.id)}
+                                                                                class="mt-1 h-4 w-4 rounded border-border text-primary focus:ring-primary disabled:cursor-not-allowed"
+                                                                            />
+                                                                            <div class="min-w-0">
+                                                                                <div class="font-medium text-foreground">{subScope.name}</div>
+                                                                                <div class="text-xs text-muted-foreground">Exclude only this sub-scope.</div>
+                                                                            </div>
+                                                                        </label>
+                                                                    )}
+                                                                </For>
+                                                            </div>
+                                                        </Show>
+                                                    </div>
+                                                );
+                                            }}
+                                        </For>
+                                    </div>
+                                </Show>
+                            </div>
+
+                            <div class="p-6 bg-muted/20 border-t border-border/50 flex justify-end gap-3">
+                                <button
+                                    onClick={closeCsvImportModal}
+                                    class="px-5 py-2.5 rounded-xl font-bold text-sm hover:bg-background transition-colors"
+                                >
+                                    Cancel
+                                </button>
+                                <button
+                                    onClick={confirmCsvImport}
+                                    class="px-5 py-2.5 bg-primary text-primary-foreground rounded-xl font-bold text-sm shadow-premium hover:shadow-premium-hover transition-all"
+                                >
+                                    Import Quantities
+                                </button>
+                            </div>
+                        </div>
+                    </div>
+                </Portal>
+            </Show>
             
             <NewEstimateModal 
                 show={showNewEstimateModal()}